<?xml version="1.0" encoding="UTF-8"?>

<!--XBRL Document Created with the Workiva Platform-->
<!--Copyright 2024 Workiva-->
<!--r:f978b62b-0b5d-4525-9c9a-353eb8961492,g:e9e8e764-a5ea-4370-854e-7ce6a9aa54a1-->
<link:linkbase xmlns:link="http://www.xbrl.org/2003/linkbase" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:xbrldt="http://xbrl.org/2005/xbrldt" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/all" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#all"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#hypercube-dimension"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-default"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#dimension-domain"/>
  <link:arcroleRef arcroleURI="http://xbrl.org/int/dim/arcrole/domain-member" xlink:type="simple" xlink:href="http://www.xbrl.org/2005/xbrldt-2005.xsd#domain-member"/>
  <link:roleRef roleURI="http://www.gibraltar1.com/role/ConsolidatedStatementsofStockholdersEquity" xlink:type="simple" xlink:href="rock-20231231.xsd#ConsolidatedStatementsofStockholdersEquity"/>
  <link:definitionLink xlink:role="http://www.gibraltar1.com/role/ConsolidatedStatementsofStockholdersEquity" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementLineItems_b473df22-1795-4c94-931f-2afd43969067" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementTable_718df76e-34af-4c7e-b60a-fc6680fc93c4" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_StatementLineItems_b473df22-1795-4c94-931f-2afd43969067" xlink:to="loc_us-gaap_StatementTable_718df76e-34af-4c7e-b60a-fc6680fc93c4" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_2ce124c2-03ef-4d27-998c-226e4dfb2edc" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_StatementTable_718df76e-34af-4c7e-b60a-fc6680fc93c4" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_2ce124c2-03ef-4d27-998c-226e4dfb2edc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_2ce124c2-03ef-4d27-998c-226e4dfb2edc_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_2ce124c2-03ef-4d27-998c-226e4dfb2edc" xlink:to="loc_us-gaap_EquityComponentDomain_2ce124c2-03ef-4d27-998c-226e4dfb2edc_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_709c2493-2d11-49dc-a763-5e091e853d4a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_2ce124c2-03ef-4d27-998c-226e4dfb2edc" xlink:to="loc_us-gaap_EquityComponentDomain_709c2493-2d11-49dc-a763-5e091e853d4a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember_89d8da83-6d9b-4ad6-baa8-876dac74d6f5" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommonStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_709c2493-2d11-49dc-a763-5e091e853d4a" xlink:to="loc_us-gaap_CommonStockMember_89d8da83-6d9b-4ad6-baa8-876dac74d6f5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdditionalPaidInCapitalMember_e0ea28e5-8e94-4f09-833b-8d8c432704be" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AdditionalPaidInCapitalMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_709c2493-2d11-49dc-a763-5e091e853d4a" xlink:to="loc_us-gaap_AdditionalPaidInCapitalMember_e0ea28e5-8e94-4f09-833b-8d8c432704be" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsMember_95544ebd-99af-44a1-aac4-66548b0f3e1f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RetainedEarningsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_709c2493-2d11-49dc-a763-5e091e853d4a" xlink:to="loc_us-gaap_RetainedEarningsMember_95544ebd-99af-44a1-aac4-66548b0f3e1f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_897d5172-fe25-4b70-b3cd-7a62df69b5bf" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_709c2493-2d11-49dc-a763-5e091e853d4a" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeMember_897d5172-fe25-4b70-b3cd-7a62df69b5bf" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockCommonMember_6443e18c-15de-46dc-9449-e8745f291732" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TreasuryStockCommonMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_709c2493-2d11-49dc-a763-5e091e853d4a" xlink:to="loc_us-gaap_TreasuryStockCommonMember_6443e18c-15de-46dc-9449-e8745f291732" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_998dee0f-522b-4d35-9e35-2724e8a5f018" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncreaseDecreaseInStockholdersEquityRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_b473df22-1795-4c94-931f-2afd43969067" xlink:to="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_998dee0f-522b-4d35-9e35-2724e8a5f018" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharesIssued_a582abd5-510f-4224-8f3c-7f0c134ddc6c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SharesIssued"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_998dee0f-522b-4d35-9e35-2724e8a5f018" xlink:to="loc_us-gaap_SharesIssued_a582abd5-510f-4224-8f3c-7f0c134ddc6c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_2e65ce50-9400-4f78-8463-5740c1e0a8d7" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockholdersEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_998dee0f-522b-4d35-9e35-2724e8a5f018" xlink:to="loc_us-gaap_StockholdersEquity_2e65ce50-9400-4f78-8463-5740c1e0a8d7" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLoss_113359e2-bb5d-479f-852a-7bbdebfcff1c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_NetIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_998dee0f-522b-4d35-9e35-2724e8a5f018" xlink:to="loc_us-gaap_NetIncomeLoss_113359e2-bb5d-479f-852a-7bbdebfcff1c" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax_4d243beb-5f2f-4b4c-93d3-60721f5b202a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_998dee0f-522b-4d35-9e35-2724e8a5f018" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossForeignCurrencyTransactionAndTranslationAdjustmentNetOfTax_4d243beb-5f2f-4b4c-93d3-60721f5b202a" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax_16282866-e7af-4f81-8363-dabd88de7602" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_998dee0f-522b-4d35-9e35-2724e8a5f018" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentNetOfTax_16282866-e7af-4f81-8363-dabd88de7602" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_5ca1180c-b218-4f11-bef7-95f70557e0e9" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_998dee0f-522b-4d35-9e35-2724e8a5f018" xlink:to="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalSharebasedCompensationRequisiteServicePeriodRecognitionValue_5ca1180c-b218-4f11-bef7-95f70557e0e9" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_StockIssuedDuringPeriodSharesRestrictedStockAwardSettlement_4d0b67e8-efc0-4bd5-83b6-0799f1a9f36f" xlink:href="rock-20231231.xsd#rock_StockIssuedDuringPeriodSharesRestrictedStockAwardSettlement"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_998dee0f-522b-4d35-9e35-2724e8a5f018" xlink:to="loc_rock_StockIssuedDuringPeriodSharesRestrictedStockAwardSettlement_4d0b67e8-efc0-4bd5-83b6-0799f1a9f36f" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_StockIssuedDuringPeriodValueRestrictedStockAwardSettlement_09275cd3-237f-4664-85a3-cd6b72bc99e9" xlink:href="rock-20231231.xsd#rock_StockIssuedDuringPeriodValueRestrictedStockAwardSettlement"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_998dee0f-522b-4d35-9e35-2724e8a5f018" xlink:to="loc_rock_StockIssuedDuringPeriodValueRestrictedStockAwardSettlement_09275cd3-237f-4664-85a3-cd6b72bc99e9" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesOther_076950aa-2c75-4682-99d1-8a7452ca1124" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockIssuedDuringPeriodSharesOther"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_998dee0f-522b-4d35-9e35-2724e8a5f018" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesOther_076950aa-2c75-4682-99d1-8a7452ca1124" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockRepurchasedDuringPeriodShares_a04c9ec1-3e5a-4467-8a85-8abfd9126221" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockRepurchasedDuringPeriodShares"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_998dee0f-522b-4d35-9e35-2724e8a5f018" xlink:to="loc_us-gaap_StockRepurchasedDuringPeriodShares_a04c9ec1-3e5a-4467-8a85-8abfd9126221" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockRepurchasedDuringPeriodValue_188e85df-a5d7-4e0e-a616-33721026a910" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockRepurchasedDuringPeriodValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_998dee0f-522b-4d35-9e35-2724e8a5f018" xlink:to="loc_us-gaap_StockRepurchasedDuringPeriodValue_188e85df-a5d7-4e0e-a616-33721026a910" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_a8ceff41-b424-4af0-b40d-35614f8655a9" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_998dee0f-522b-4d35-9e35-2724e8a5f018" xlink:to="loc_us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_a8ceff41-b424-4af0-b40d-35614f8655a9" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised_b6a457d0-9dd5-4256-82bf-38249cf9d475" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_998dee0f-522b-4d35-9e35-2724e8a5f018" xlink:to="loc_us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised_b6a457d0-9dd5-4256-82bf-38249cf9d475" xlink:type="arc" order="13"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_TreasuryStockValueAcquiredExciseTaxAmountCostMethod_7c8beb27-d2e5-448d-9655-6c3ee1302e93" xlink:href="rock-20231231.xsd#rock_TreasuryStockValueAcquiredExciseTaxAmountCostMethod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncreaseDecreaseInStockholdersEquityRollForward_998dee0f-522b-4d35-9e35-2724e8a5f018" xlink:to="loc_rock_TreasuryStockValueAcquiredExciseTaxAmountCostMethod_7c8beb27-d2e5-448d-9655-6c3ee1302e93" xlink:type="arc" order="14"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharesIssued_703ea2e0-ea0e-4df0-8c1f-29ca6ab9cbc6" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SharesIssued"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_4066d018-66ba-4f9f-a3af-300b784d09c6" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockholdersEquity"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_OtherComprehensiveIncomeMinimumPensionLiabilityNetAdjustmentTax1_400fec63-8e76-4f6b-8e8c-3cee27b9c423" xlink:href="rock-20231231.xsd#rock_OtherComprehensiveIncomeMinimumPensionLiabilityNetAdjustmentTax1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_StatementLineItems_b473df22-1795-4c94-931f-2afd43969067" xlink:to="loc_rock_OtherComprehensiveIncomeMinimumPensionLiabilityNetAdjustmentTax1_400fec63-8e76-4f6b-8e8c-3cee27b9c423" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.gibraltar1.com/role/PensionandOtherPostretirementBenefitsTables" xlink:type="simple" xlink:href="rock-20231231.xsd#PensionandOtherPostretirementBenefitsTables"/>
  <link:definitionLink xlink:role="http://www.gibraltar1.com/role/PensionandOtherPostretirementBenefitsTables" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems_309d8b8d-5452-4008-99e5-2a1f3d84f0c9" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansDisclosuresTable_6253a407-435a-401f-ba6b-0e7e880dad22" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansDisclosuresTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems_309d8b8d-5452-4008-99e5-2a1f3d84f0c9" xlink:to="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansDisclosuresTable_6253a407-435a-401f-ba6b-0e7e880dad22" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeAxis_e8ae53bb-1ad6-4e3b-84c5-01eba74c35df" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RetirementPlanTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansDisclosuresTable_6253a407-435a-401f-ba6b-0e7e880dad22" xlink:to="loc_us-gaap_RetirementPlanTypeAxis_e8ae53bb-1ad6-4e3b-84c5-01eba74c35df" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_e8ae53bb-1ad6-4e3b-84c5-01eba74c35df_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RetirementPlanTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_e8ae53bb-1ad6-4e3b-84c5-01eba74c35df" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_e8ae53bb-1ad6-4e3b-84c5-01eba74c35df_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_a997fb65-650d-4678-9432-6d54c7426f61" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RetirementPlanTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_e8ae53bb-1ad6-4e3b-84c5-01eba74c35df" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_a997fb65-650d-4678-9432-6d54c7426f61" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPostretirementHealthCoverageMember_83524564-301a-447d-89b1-3c449e0f4828" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPostretirementHealthCoverageMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanTypeDomain_a997fb65-650d-4678-9432-6d54c7426f61" xlink:to="loc_us-gaap_DefinedBenefitPostretirementHealthCoverageMember_83524564-301a-447d-89b1-3c449e0f4828" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfCostsOfRetirementPlansTableTextBlock_c5d1f036-04e5-402e-8af6-1141c177881f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfCostsOfRetirementPlansTableTextBlock"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems_309d8b8d-5452-4008-99e5-2a1f3d84f0c9" xlink:to="loc_us-gaap_ScheduleOfCostsOfRetirementPlansTableTextBlock_c5d1f036-04e5-402e-8af6-1141c177881f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfNetFundedStatusTableTextBlock_f4c99a6c-a1c9-4db0-8cdd-74ad12e4179d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfNetFundedStatusTableTextBlock"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems_309d8b8d-5452-4008-99e5-2a1f3d84f0c9" xlink:to="loc_us-gaap_ScheduleOfNetFundedStatusTableTextBlock_f4c99a6c-a1c9-4db0-8cdd-74ad12e4179d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAmountsRecognizedInBalanceSheetTableTextBlock_bf58c8f8-e80c-460c-b090-e5f52d7bcdcb" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfAmountsRecognizedInBalanceSheetTableTextBlock"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems_309d8b8d-5452-4008-99e5-2a1f3d84f0c9" xlink:to="loc_us-gaap_ScheduleOfAmountsRecognizedInBalanceSheetTableTextBlock_bf58c8f8-e80c-460c-b090-e5f52d7bcdcb" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfNetBenefitCostsTableTextBlock_04c5d9fd-a639-40cc-819c-45af5b974822" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfNetBenefitCostsTableTextBlock"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems_309d8b8d-5452-4008-99e5-2a1f3d84f0c9" xlink:to="loc_us-gaap_ScheduleOfNetBenefitCostsTableTextBlock_04c5d9fd-a639-40cc-819c-45af5b974822" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfExpectedBenefitPaymentsTableTextBlock_7941286e-a5d5-44f8-a1b8-7d5645ae96d6" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfExpectedBenefitPaymentsTableTextBlock"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems_309d8b8d-5452-4008-99e5-2a1f3d84f0c9" xlink:to="loc_us-gaap_ScheduleOfExpectedBenefitPaymentsTableTextBlock_7941286e-a5d5-44f8-a1b8-7d5645ae96d6" xlink:type="arc" order="4"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.gibraltar1.com/role/SummaryofSignificantAccountingPoliciesNarrativeDetails" xlink:type="simple" xlink:href="rock-20231231.xsd#SummaryofSignificantAccountingPoliciesNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.gibraltar1.com/role/SummaryofSignificantAccountingPoliciesNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SaleLeasebackTransactionLineItems_1f6d3411-f5cf-4e1c-a26f-85ab5852d19a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SaleLeasebackTransactionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SaleLeasebackTransactionTable_cb64e218-9ff7-4d61-afbb-45927352c0c2" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SaleLeasebackTransactionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SaleLeasebackTransactionLineItems_1f6d3411-f5cf-4e1c-a26f-85ab5852d19a" xlink:to="loc_us-gaap_SaleLeasebackTransactionTable_cb64e218-9ff7-4d61-afbb-45927352c0c2" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_c1308726-b032-4d0f-8394-4e219894a1d5" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SaleLeasebackTransactionTable_cb64e218-9ff7-4d61-afbb-45927352c0c2" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_c1308726-b032-4d0f-8394-4e219894a1d5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_c1308726-b032-4d0f-8394-4e219894a1d5_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_c1308726-b032-4d0f-8394-4e219894a1d5" xlink:to="loc_us-gaap_EquityComponentDomain_c1308726-b032-4d0f-8394-4e219894a1d5_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_d1a515be-44e2-4428-89d1-79b25083f3ce" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_c1308726-b032-4d0f-8394-4e219894a1d5" xlink:to="loc_us-gaap_EquityComponentDomain_d1a515be-44e2-4428-89d1-79b25083f3ce" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsMember_9a2163d0-29d7-4c99-a48c-d01fca700911" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RetainedEarningsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_d1a515be-44e2-4428-89d1-79b25083f3ce" xlink:to="loc_us-gaap_RetainedEarningsMember_9a2163d0-29d7-4c99-a48c-d01fca700911" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_63fd3047-02a9-46ca-9d2a-b2af9d43cf88" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SaleLeasebackTransactionTable_cb64e218-9ff7-4d61-afbb-45927352c0c2" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_63fd3047-02a9-46ca-9d2a-b2af9d43cf88" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_63fd3047-02a9-46ca-9d2a-b2af9d43cf88_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_63fd3047-02a9-46ca-9d2a-b2af9d43cf88" xlink:to="loc_us-gaap_SegmentDomain_63fd3047-02a9-46ca-9d2a-b2af9d43cf88_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_2a0a9465-8e11-49b5-9be5-835893a34251" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_63fd3047-02a9-46ca-9d2a-b2af9d43cf88" xlink:to="loc_us-gaap_SegmentDomain_2a0a9465-8e11-49b5-9be5-835893a34251" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_ResidentialMember_35543c99-87f7-4a2c-9aaf-85843ea0fc79" xlink:href="rock-20231231.xsd#rock_ResidentialMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_2a0a9465-8e11-49b5-9be5-835893a34251" xlink:to="loc_rock_ResidentialMember_35543c99-87f7-4a2c-9aaf-85843ea0fc79" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MajorCustomersAxis_e7c38ff4-a2c0-48fd-b341-c89971a25fdc" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_MajorCustomersAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SaleLeasebackTransactionTable_cb64e218-9ff7-4d61-afbb-45927352c0c2" xlink:to="loc_srt_MajorCustomersAxis_e7c38ff4-a2c0-48fd-b341-c89971a25fdc" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_e7c38ff4-a2c0-48fd-b341-c89971a25fdc_default" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_NameOfMajorCustomerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_MajorCustomersAxis_e7c38ff4-a2c0-48fd-b341-c89971a25fdc" xlink:to="loc_srt_NameOfMajorCustomerDomain_e7c38ff4-a2c0-48fd-b341-c89971a25fdc_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NameOfMajorCustomerDomain_b02979f6-da97-41b3-a2a0-ead02d85ec6a" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_NameOfMajorCustomerDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_MajorCustomersAxis_e7c38ff4-a2c0-48fd-b341-c89971a25fdc" xlink:to="loc_srt_NameOfMajorCustomerDomain_b02979f6-da97-41b3-a2a0-ead02d85ec6a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_HomeImprovementRetailCompanyMember_a57fa505-fcb5-40f7-8579-25874f40916e" xlink:href="rock-20231231.xsd#rock_HomeImprovementRetailCompanyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_NameOfMajorCustomerDomain_b02979f6-da97-41b3-a2a0-ead02d85ec6a" xlink:to="loc_rock_HomeImprovementRetailCompanyMember_a57fa505-fcb5-40f7-8579-25874f40916e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_7c711114-9176-49ea-8727-d209005b20d8" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ConcentrationRiskByBenchmarkAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SaleLeasebackTransactionTable_cb64e218-9ff7-4d61-afbb-45927352c0c2" xlink:to="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_7c711114-9176-49ea-8727-d209005b20d8" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_7c711114-9176-49ea-8727-d209005b20d8_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ConcentrationRiskBenchmarkDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_7c711114-9176-49ea-8727-d209005b20d8" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_7c711114-9176-49ea-8727-d209005b20d8_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskBenchmarkDomain_e4261a79-d0ae-4415-ab3f-81f2ad33610f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ConcentrationRiskBenchmarkDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByBenchmarkAxis_7c711114-9176-49ea-8727-d209005b20d8" xlink:to="loc_us-gaap_ConcentrationRiskBenchmarkDomain_e4261a79-d0ae-4415-ab3f-81f2ad33610f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountsReceivableMember_8117cba5-0f6b-4280-a46b-9e7a01a023bf" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccountsReceivableMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskBenchmarkDomain_e4261a79-d0ae-4415-ab3f-81f2ad33610f" xlink:to="loc_us-gaap_AccountsReceivableMember_8117cba5-0f6b-4280-a46b-9e7a01a023bf" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SalesRevenueNetMember_7b6a419a-af78-44c4-8bf6-3015bd342911" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SalesRevenueNetMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskBenchmarkDomain_e4261a79-d0ae-4415-ab3f-81f2ad33610f" xlink:to="loc_us-gaap_SalesRevenueNetMember_7b6a419a-af78-44c4-8bf6-3015bd342911" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_9e9ba4a9-9a7b-4fef-89f6-2e844d0ee409" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SaleLeasebackTransactionTable_cb64e218-9ff7-4d61-afbb-45927352c0c2" xlink:to="loc_srt_RangeAxis_9e9ba4a9-9a7b-4fef-89f6-2e844d0ee409" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_9e9ba4a9-9a7b-4fef-89f6-2e844d0ee409_default" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_9e9ba4a9-9a7b-4fef-89f6-2e844d0ee409" xlink:to="loc_srt_RangeMember_9e9ba4a9-9a7b-4fef-89f6-2e844d0ee409_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_22e99f46-37df-47e8-9f44-7a35fc3500ae" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_9e9ba4a9-9a7b-4fef-89f6-2e844d0ee409" xlink:to="loc_srt_RangeMember_22e99f46-37df-47e8-9f44-7a35fc3500ae" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_59a6c667-8048-4f2a-ab22-bdaaa71be887" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_22e99f46-37df-47e8-9f44-7a35fc3500ae" xlink:to="loc_srt_MinimumMember_59a6c667-8048-4f2a-ab22-bdaaa71be887" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_f3cb41a3-300d-4470-82ff-ce153f7480d8" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_22e99f46-37df-47e8-9f44-7a35fc3500ae" xlink:to="loc_srt_MaximumMember_f3cb41a3-300d-4470-82ff-ce153f7480d8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_3e479a06-251b-4f05-b56d-e1f2cff01ad8" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PropertyPlantAndEquipmentByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SaleLeasebackTransactionTable_cb64e218-9ff7-4d61-afbb-45927352c0c2" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_3e479a06-251b-4f05-b56d-e1f2cff01ad8" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_3e479a06-251b-4f05-b56d-e1f2cff01ad8_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_3e479a06-251b-4f05-b56d-e1f2cff01ad8" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_3e479a06-251b-4f05-b56d-e1f2cff01ad8_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_6dca903b-266c-4128-8bbd-d67a4837ca05" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PropertyPlantAndEquipmentTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentByTypeAxis_3e479a06-251b-4f05-b56d-e1f2cff01ad8" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_6dca903b-266c-4128-8bbd-d67a4837ca05" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LandBuildingsAndImprovementsMember_e3759125-9ff4-4f20-960e-1571f05fcf0a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LandBuildingsAndImprovementsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_6dca903b-266c-4128-8bbd-d67a4837ca05" xlink:to="loc_us-gaap_LandBuildingsAndImprovementsMember_e3759125-9ff4-4f20-960e-1571f05fcf0a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MachineryAndEquipmentMember_922ec64c-7cd9-49d6-8130-2c7ad2c58250" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_MachineryAndEquipmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTypeDomain_6dca903b-266c-4128-8bbd-d67a4837ca05" xlink:to="loc_us-gaap_MachineryAndEquipmentMember_922ec64c-7cd9-49d6-8130-2c7ad2c58250" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskByTypeAxis_a9a0d556-6041-4e1d-8a50-9713a0d5e30f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ConcentrationRiskByTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_SaleLeasebackTransactionTable_cb64e218-9ff7-4d61-afbb-45927352c0c2" xlink:to="loc_us-gaap_ConcentrationRiskByTypeAxis_a9a0d556-6041-4e1d-8a50-9713a0d5e30f" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_a9a0d556-6041-4e1d-8a50-9713a0d5e30f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ConcentrationRiskTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_a9a0d556-6041-4e1d-8a50-9713a0d5e30f" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_a9a0d556-6041-4e1d-8a50-9713a0d5e30f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskTypeDomain_fb3eadc9-fe36-4c1a-931f-abdfbf04e03c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ConcentrationRiskTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ConcentrationRiskByTypeAxis_a9a0d556-6041-4e1d-8a50-9713a0d5e30f" xlink:to="loc_us-gaap_ConcentrationRiskTypeDomain_fb3eadc9-fe36-4c1a-931f-abdfbf04e03c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CustomerConcentrationRiskMember_8396345d-67c5-4edc-a6e6-83646b412df3" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CustomerConcentrationRiskMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ConcentrationRiskTypeDomain_fb3eadc9-fe36-4c1a-931f-abdfbf04e03c" xlink:to="loc_us-gaap_CustomerConcentrationRiskMember_8396345d-67c5-4edc-a6e6-83646b412df3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NumberOfReportableSegments_73bc7903-cd2b-4ce5-8901-dd98b8b26eeb" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_NumberOfReportableSegments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SaleLeasebackTransactionLineItems_1f6d3411-f5cf-4e1c-a26f-85ab5852d19a" xlink:to="loc_us-gaap_NumberOfReportableSegments_73bc7903-cd2b-4ce5-8901-dd98b8b26eeb" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ConcentrationRiskPercentage1_054a87b3-e60f-467e-a677-d70b38577873" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ConcentrationRiskPercentage1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SaleLeasebackTransactionLineItems_1f6d3411-f5cf-4e1c-a26f-85ab5852d19a" xlink:to="loc_us-gaap_ConcentrationRiskPercentage1_054a87b3-e60f-467e-a677-d70b38577873" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentUsefulLife_925f969b-b8fc-47fc-8463-f20144cf39ba" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PropertyPlantAndEquipmentUsefulLife"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SaleLeasebackTransactionLineItems_1f6d3411-f5cf-4e1c-a26f-85ab5852d19a" xlink:to="loc_us-gaap_PropertyPlantAndEquipmentUsefulLife_925f969b-b8fc-47fc-8463-f20144cf39ba" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdvertisingExpense_a6d38e0b-5817-40a4-bbb8-8e8edf16baa2" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AdvertisingExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SaleLeasebackTransactionLineItems_1f6d3411-f5cf-4e1c-a26f-85ab5852d19a" xlink:to="loc_us-gaap_AdvertisingExpense_a6d38e0b-5817-40a4-bbb8-8e8edf16baa2" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.gibraltar1.com/role/RevenueNarrativeDetails" xlink:type="simple" xlink:href="rock-20231231.xsd#RevenueNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.gibraltar1.com/role/RevenueNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CapitalizedContractCostLineItems_9eb7ff9a-de7f-44bf-a569-7cb2cb4b351a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CapitalizedContractCostLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CapitalizedContractCostTable_36fbd152-de04-4f5e-8717-6bbbbb3a2ab7" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CapitalizedContractCostTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_CapitalizedContractCostLineItems_9eb7ff9a-de7f-44bf-a569-7cb2cb4b351a" xlink:to="loc_us-gaap_CapitalizedContractCostTable_36fbd152-de04-4f5e-8717-6bbbbb3a2ab7" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_6c9bb7a8-043f-4202-9d4a-79754660426b" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_CapitalizedContractCostTable_36fbd152-de04-4f5e-8717-6bbbbb3a2ab7" xlink:to="loc_srt_RangeAxis_6c9bb7a8-043f-4202-9d4a-79754660426b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_6c9bb7a8-043f-4202-9d4a-79754660426b_default" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_6c9bb7a8-043f-4202-9d4a-79754660426b" xlink:to="loc_srt_RangeMember_6c9bb7a8-043f-4202-9d4a-79754660426b_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_739cb022-625b-4dec-a793-249ceb1aedb5" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_6c9bb7a8-043f-4202-9d4a-79754660426b" xlink:to="loc_srt_RangeMember_739cb022-625b-4dec-a793-249ceb1aedb5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_29427c55-4acd-427f-aee6-0291ba119589" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_739cb022-625b-4dec-a793-249ceb1aedb5" xlink:to="loc_srt_MinimumMember_29427c55-4acd-427f-aee6-0291ba119589" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_70203784-94d1-494f-be60-0103ff794c40" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_739cb022-625b-4dec-a793-249ceb1aedb5" xlink:to="loc_srt_MaximumMember_70203784-94d1-494f-be60-0103ff794c40" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationAxis_bc2b7aa3-48a8-4dc4-b23c-ff65ee293484" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BalanceSheetLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_CapitalizedContractCostTable_36fbd152-de04-4f5e-8717-6bbbbb3a2ab7" xlink:to="loc_us-gaap_BalanceSheetLocationAxis_bc2b7aa3-48a8-4dc4-b23c-ff65ee293484" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_bc2b7aa3-48a8-4dc4-b23c-ff65ee293484_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_bc2b7aa3-48a8-4dc4-b23c-ff65ee293484" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_bc2b7aa3-48a8-4dc4-b23c-ff65ee293484_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_7fde3e29-d2b3-4f4d-ace4-6b086a136b77" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_bc2b7aa3-48a8-4dc4-b23c-ff65ee293484" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_7fde3e29-d2b3-4f4d-ace4-6b086a136b77" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_BillingsinExcessofCostMember_37030a5c-4b5d-4f56-81cb-969552567236" xlink:href="rock-20231231.xsd#rock_BillingsinExcessofCostMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_7fde3e29-d2b3-4f4d-ace4-6b086a136b77" xlink:to="loc_rock_BillingsinExcessofCostMember_37030a5c-4b5d-4f56-81cb-969552567236" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_ContractWithCustomerContractPaymentTerms_7655eb1a-b0f6-4385-bf82-0dd52b482c8b" xlink:href="rock-20231231.xsd#rock_ContractWithCustomerContractPaymentTerms"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CapitalizedContractCostLineItems_9eb7ff9a-de7f-44bf-a569-7cb2cb4b351a" xlink:to="loc_rock_ContractWithCustomerContractPaymentTerms_7655eb1a-b0f6-4385-bf82-0dd52b482c8b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1_af9b89c4-2cca-4298-8c4d-6c99351eb841" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CapitalizedContractCostLineItems_9eb7ff9a-de7f-44bf-a569-7cb2cb4b351a" xlink:to="loc_us-gaap_RevenueRemainingPerformanceObligationExpectedTimingOfSatisfactionPeriod1_af9b89c4-2cca-4298-8c4d-6c99351eb841" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_ContractWithCustomerAssetObtainedThroughIncrementalCostOfObtainingContract_e9fb451a-0223-43e1-b724-a817b9405829" xlink:href="rock-20231231.xsd#rock_ContractWithCustomerAssetObtainedThroughIncrementalCostOfObtainingContract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CapitalizedContractCostLineItems_9eb7ff9a-de7f-44bf-a569-7cb2cb4b351a" xlink:to="loc_rock_ContractWithCustomerAssetObtainedThroughIncrementalCostOfObtainingContract_e9fb451a-0223-43e1-b724-a817b9405829" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerAssetNet_77c5e30e-f3cf-4059-8d51-944c262df2af" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ContractWithCustomerAssetNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CapitalizedContractCostLineItems_9eb7ff9a-de7f-44bf-a569-7cb2cb4b351a" xlink:to="loc_us-gaap_ContractWithCustomerAssetNet_77c5e30e-f3cf-4059-8d51-944c262df2af" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerLiability_df817c41-9973-4b12-9192-695a8b607eb2" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ContractWithCustomerLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CapitalizedContractCostLineItems_9eb7ff9a-de7f-44bf-a569-7cb2cb4b351a" xlink:to="loc_us-gaap_ContractWithCustomerLiability_df817c41-9973-4b12-9192-695a8b607eb2" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerAssetReclassifiedToReceivable_07bf7857-a0ff-443d-bfaa-3b1dd1f3a54b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ContractWithCustomerAssetReclassifiedToReceivable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CapitalizedContractCostLineItems_9eb7ff9a-de7f-44bf-a569-7cb2cb4b351a" xlink:to="loc_us-gaap_ContractWithCustomerAssetReclassifiedToReceivable_07bf7857-a0ff-443d-bfaa-3b1dd1f3a54b" xlink:type="arc" order="5"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.gibraltar1.com/role/RevenueContractAssetsandLiabilitiesDetails" xlink:type="simple" xlink:href="rock-20231231.xsd#RevenueContractAssetsandLiabilitiesDetails"/>
  <link:definitionLink xlink:role="http://www.gibraltar1.com/role/RevenueContractAssetsandLiabilitiesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CapitalizedContractCostLineItems_94bd967b-12dc-441b-8fd3-810a292148f5" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CapitalizedContractCostLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CapitalizedContractCostTable_04c07aac-34c0-404d-83d4-60ac80cefa45" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CapitalizedContractCostTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_CapitalizedContractCostLineItems_94bd967b-12dc-441b-8fd3-810a292148f5" xlink:to="loc_us-gaap_CapitalizedContractCostTable_04c07aac-34c0-404d-83d4-60ac80cefa45" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationAxis_f1eb6db9-daaf-4483-9951-3c43154b6573" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BalanceSheetLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_CapitalizedContractCostTable_04c07aac-34c0-404d-83d4-60ac80cefa45" xlink:to="loc_us-gaap_BalanceSheetLocationAxis_f1eb6db9-daaf-4483-9951-3c43154b6573" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_f1eb6db9-daaf-4483-9951-3c43154b6573_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_f1eb6db9-daaf-4483-9951-3c43154b6573" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_f1eb6db9-daaf-4483-9951-3c43154b6573_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_8cf34bd0-2d60-44b9-a2dc-257fee29bb84" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_f1eb6db9-daaf-4483-9951-3c43154b6573" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_8cf34bd0-2d60-44b9-a2dc-257fee29bb84" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_BillingsinExcessofCostMember_efed2bd7-c8ce-43f2-90c2-d2b9e6b2dabd" xlink:href="rock-20231231.xsd#rock_BillingsinExcessofCostMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_8cf34bd0-2d60-44b9-a2dc-257fee29bb84" xlink:to="loc_rock_BillingsinExcessofCostMember_efed2bd7-c8ce-43f2-90c2-d2b9e6b2dabd" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerAssetNet_01fe717f-0ab7-4ebe-9545-84284a785e5d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ContractWithCustomerAssetNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CapitalizedContractCostLineItems_94bd967b-12dc-441b-8fd3-810a292148f5" xlink:to="loc_us-gaap_ContractWithCustomerAssetNet_01fe717f-0ab7-4ebe-9545-84284a785e5d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractWithCustomerLiability_d1190f2c-578f-41ec-957a-2548df619a3c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ContractWithCustomerLiability"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CapitalizedContractCostLineItems_94bd967b-12dc-441b-8fd3-810a292148f5" xlink:to="loc_us-gaap_ContractWithCustomerLiability_d1190f2c-578f-41ec-957a-2548df619a3c" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.gibraltar1.com/role/AcquisitionsNarrativeDetails" xlink:type="simple" xlink:href="rock-20231231.xsd#AcquisitionsNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.gibraltar1.com/role/AcquisitionsNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionLineItems_5befe430-78a2-4d48-8156-48ed5a38e79c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessAcquisitionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_fcfc9b2b-4693-401f-ad79-072cfff205df" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_5befe430-78a2-4d48-8156-48ed5a38e79c" xlink:to="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_fcfc9b2b-4693-401f-ad79-072cfff205df" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_aba23be4-0d1b-455c-bd0a-f3f9e170f370" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessAcquisitionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_fcfc9b2b-4693-401f-ad79-072cfff205df" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_aba23be4-0d1b-455c-bd0a-f3f9e170f370" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_aba23be4-0d1b-455c-bd0a-f3f9e170f370_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_aba23be4-0d1b-455c-bd0a-f3f9e170f370" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_aba23be4-0d1b-455c-bd0a-f3f9e170f370_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_be531681-f8a9-4540-bf1a-2458195d0960" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_aba23be4-0d1b-455c-bd0a-f3f9e170f370" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_be531681-f8a9-4540-bf1a-2458195d0960" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_QualityAluminumProductsMember_3156eb30-125d-49b6-aaba-e59a4abdd5f0" xlink:href="rock-20231231.xsd#rock_QualityAluminumProductsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_be531681-f8a9-4540-bf1a-2458195d0960" xlink:to="loc_rock_QualityAluminumProductsMember_3156eb30-125d-49b6-aaba-e59a4abdd5f0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_PrivatelyHeldUtahBasedCompanyMember_cef725d3-12af-4ed1-b536-bf89919d60d7" xlink:href="rock-20231231.xsd#rock_PrivatelyHeldUtahBasedCompanyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_be531681-f8a9-4540-bf1a-2458195d0960" xlink:to="loc_rock_PrivatelyHeldUtahBasedCompanyMember_cef725d3-12af-4ed1-b536-bf89919d60d7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_c040e7f7-07e2-4858-ab96-ea37b8c642fb" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeStatementLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_fcfc9b2b-4693-401f-ad79-072cfff205df" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_c040e7f7-07e2-4858-ab96-ea37b8c642fb" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_c040e7f7-07e2-4858-ab96-ea37b8c642fb_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_c040e7f7-07e2-4858-ab96-ea37b8c642fb" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_c040e7f7-07e2-4858-ab96-ea37b8c642fb_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_c3d2e3a8-ff29-4b3e-be50-9a42228ce1fc" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_c040e7f7-07e2-4858-ab96-ea37b8c642fb" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_c3d2e3a8-ff29-4b3e-be50-9a42228ce1fc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SellingGeneralAndAdministrativeExpensesMember_879f6d93-69cf-45c2-a695-24ad0909f08f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SellingGeneralAndAdministrativeExpensesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_c3d2e3a8-ff29-4b3e-be50-9a42228ce1fc" xlink:to="loc_us-gaap_SellingGeneralAndAdministrativeExpensesMember_879f6d93-69cf-45c2-a695-24ad0909f08f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationConsiderationTransferred1_001723d1-7055-426a-b807-56303f267ab8" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessCombinationConsiderationTransferred1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_5befe430-78a2-4d48-8156-48ed5a38e79c" xlink:to="loc_us-gaap_BusinessCombinationConsiderationTransferred1_001723d1-7055-426a-b807-56303f267ab8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Goodwill_36b5ecac-1e99-4b90-badd-fd207d6a6adc" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_Goodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_5befe430-78a2-4d48-8156-48ed5a38e79c" xlink:to="loc_us-gaap_Goodwill_36b5ecac-1e99-4b90-badd-fd207d6a6adc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_FairValueMeasurementPeriod_27db59bd-052d-4089-a747-7acdc8788d32" xlink:href="rock-20231231.xsd#rock_FairValueMeasurementPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_5befe430-78a2-4d48-8156-48ed5a38e79c" xlink:to="loc_rock_FairValueMeasurementPeriod_27db59bd-052d-4089-a747-7acdc8788d32" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.gibraltar1.com/role/AcquisitionsScheduleofAllocationofthePurchasePriceConsiderationoftheFairValueofAssetsAcquiredandLiabilitiesAssumedDetails" xlink:type="simple" xlink:href="rock-20231231.xsd#AcquisitionsScheduleofAllocationofthePurchasePriceConsiderationoftheFairValueofAssetsAcquiredandLiabilitiesAssumedDetails"/>
  <link:definitionLink xlink:role="http://www.gibraltar1.com/role/AcquisitionsScheduleofAllocationofthePurchasePriceConsiderationoftheFairValueofAssetsAcquiredandLiabilitiesAssumedDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionLineItems_edfac807-3d9f-4117-a7b1-feef31444e65" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessAcquisitionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_090ae82b-8589-445a-a11d-c1be7a49a581" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_edfac807-3d9f-4117-a7b1-feef31444e65" xlink:to="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_090ae82b-8589-445a-a11d-c1be7a49a581" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_e1e49eac-01ab-4bf2-976a-1eefd89a8758" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessAcquisitionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_090ae82b-8589-445a-a11d-c1be7a49a581" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_e1e49eac-01ab-4bf2-976a-1eefd89a8758" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_e1e49eac-01ab-4bf2-976a-1eefd89a8758_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_e1e49eac-01ab-4bf2-976a-1eefd89a8758" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_e1e49eac-01ab-4bf2-976a-1eefd89a8758_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_5568b799-2011-4bba-9743-9b7be48bd779" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_e1e49eac-01ab-4bf2-976a-1eefd89a8758" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_5568b799-2011-4bba-9743-9b7be48bd779" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_QualityAluminumProductsMember_a754f36b-435d-4680-950b-78f28136bb52" xlink:href="rock-20231231.xsd#rock_QualityAluminumProductsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_5568b799-2011-4bba-9743-9b7be48bd779" xlink:to="loc_rock_QualityAluminumProductsMember_a754f36b-435d-4680-950b-78f28136bb52" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_PrivatelyHeldUtahBasedCompanyMember_6824d1c3-5345-43ac-956f-7f754f98ffce" xlink:href="rock-20231231.xsd#rock_PrivatelyHeldUtahBasedCompanyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_5568b799-2011-4bba-9743-9b7be48bd779" xlink:to="loc_rock_PrivatelyHeldUtahBasedCompanyMember_6824d1c3-5345-43ac-956f-7f754f98ffce" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents_1efb6718-bedc-4929-80ed-fb2e862fe7ba" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_edfac807-3d9f-4117-a7b1-feef31444e65" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents_1efb6718-bedc-4929-80ed-fb2e862fe7ba" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_BusinessCombinationRecognizedIdentifiableAssetsAcquiredandLiabilitiesAssumedWorkingCapital_157acdda-9a3b-4519-b47e-3dce968f2ed0" xlink:href="rock-20231231.xsd#rock_BusinessCombinationRecognizedIdentifiableAssetsAcquiredandLiabilitiesAssumedWorkingCapital"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_edfac807-3d9f-4117-a7b1-feef31444e65" xlink:to="loc_rock_BusinessCombinationRecognizedIdentifiableAssetsAcquiredandLiabilitiesAssumedWorkingCapital_157acdda-9a3b-4519-b47e-3dce968f2ed0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment_c58ed9d1-f279-4f40-b470-e70b5fd8ccd1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_edfac807-3d9f-4117-a7b1-feef31444e65" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment_c58ed9d1-f279-4f40-b470-e70b5fd8ccd1" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibleAssetsOtherThanGoodwill_69f50b6e-dd14-4e90-a148-7cf252ab0707" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibleAssetsOtherThanGoodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_edfac807-3d9f-4117-a7b1-feef31444e65" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibleAssetsOtherThanGoodwill_69f50b6e-dd14-4e90-a148-7cf252ab0707" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsOther_55083fc3-4968-4f16-8bee-711d9d405f3e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsOther"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_edfac807-3d9f-4117-a7b1-feef31444e65" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsOther_55083fc3-4968-4f16-8bee-711d9d405f3e" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesOther_f0cababd-e352-47be-a74b-790948226ced" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesOther"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_edfac807-3d9f-4117-a7b1-feef31444e65" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesOther_f0cababd-e352-47be-a74b-790948226ced" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Goodwill_2009e279-1f92-46fe-8d9c-40e007d4153b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_Goodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_edfac807-3d9f-4117-a7b1-feef31444e65" xlink:to="loc_us-gaap_Goodwill_2009e279-1f92-46fe-8d9c-40e007d4153b" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet_97d465d1-4c7c-46ab-a25a-2a844803676b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_edfac807-3d9f-4117-a7b1-feef31444e65" xlink:to="loc_us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet_97d465d1-4c7c-46ab-a25a-2a844803676b" xlink:type="arc" order="7"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.gibraltar1.com/role/AcquisitionsScheduleofAcquiredIntangibleAssetsDetails" xlink:type="simple" xlink:href="rock-20231231.xsd#AcquisitionsScheduleofAcquiredIntangibleAssetsDetails"/>
  <link:definitionLink xlink:role="http://www.gibraltar1.com/role/AcquisitionsScheduleofAcquiredIntangibleAssetsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionLineItems_e203e866-eec7-404a-8303-e0890992dfe3" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessAcquisitionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_5e0fe4d6-6f1d-4012-9eb7-e1ba2bf55a00" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_e203e866-eec7-404a-8303-e0890992dfe3" xlink:to="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_5e0fe4d6-6f1d-4012-9eb7-e1ba2bf55a00" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAxis_306554a8-55f1-480c-bb7b-9863ee7a3b50" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessAcquisitionAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_5e0fe4d6-6f1d-4012-9eb7-e1ba2bf55a00" xlink:to="loc_us-gaap_BusinessAcquisitionAxis_306554a8-55f1-480c-bb7b-9863ee7a3b50" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_306554a8-55f1-480c-bb7b-9863ee7a3b50_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_306554a8-55f1-480c-bb7b-9863ee7a3b50" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_306554a8-55f1-480c-bb7b-9863ee7a3b50_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionAcquireeDomain_7cef49ca-be3e-4be5-8604-7cde8ef218a3" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessAcquisitionAcquireeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BusinessAcquisitionAxis_306554a8-55f1-480c-bb7b-9863ee7a3b50" xlink:to="loc_us-gaap_BusinessAcquisitionAcquireeDomain_7cef49ca-be3e-4be5-8604-7cde8ef218a3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_QualityAluminumProductsMember_1599a53b-5135-4196-88c7-6aa091a24aba" xlink:href="rock-20231231.xsd#rock_QualityAluminumProductsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_7cef49ca-be3e-4be5-8604-7cde8ef218a3" xlink:to="loc_rock_QualityAluminumProductsMember_1599a53b-5135-4196-88c7-6aa091a24aba" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_PrivatelyHeldUtahBasedCompanyMember_94311647-8551-4aec-9494-36c1dfb5b4e6" xlink:href="rock-20231231.xsd#rock_PrivatelyHeldUtahBasedCompanyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionAcquireeDomain_7cef49ca-be3e-4be5-8604-7cde8ef218a3" xlink:to="loc_rock_PrivatelyHeldUtahBasedCompanyMember_94311647-8551-4aec-9494-36c1dfb5b4e6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_4159d370-af11-4e62-ad00-bd4fdda76116" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_5e0fe4d6-6f1d-4012-9eb7-e1ba2bf55a00" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_4159d370-af11-4e62-ad00-bd4fdda76116" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_4159d370-af11-4e62-ad00-bd4fdda76116_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_4159d370-af11-4e62-ad00-bd4fdda76116" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_4159d370-af11-4e62-ad00-bd4fdda76116_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_602e5656-3d22-49a8-a38a-ec442aef32ef" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_4159d370-af11-4e62-ad00-bd4fdda76116" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_602e5656-3d22-49a8-a38a-ec442aef32ef" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TrademarksMember_79df9441-526d-471e-a9be-6d75c2dfaa29" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TrademarksMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_602e5656-3d22-49a8-a38a-ec442aef32ef" xlink:to="loc_us-gaap_TrademarksMember_79df9441-526d-471e-a9be-6d75c2dfaa29" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CustomerRelationshipsMember_c29d9a70-bd69-403e-9e17-310031ef8c22" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CustomerRelationshipsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_602e5656-3d22-49a8-a38a-ec442aef32ef" xlink:to="loc_us-gaap_CustomerRelationshipsMember_c29d9a70-bd69-403e-9e17-310031ef8c22" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis_3c1492aa-d823-4876-8170-9af0c70e4b26" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_5e0fe4d6-6f1d-4012-9eb7-e1ba2bf55a00" xlink:to="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis_3c1492aa-d823-4876-8170-9af0c70e4b26" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_3c1492aa-d823-4876-8170-9af0c70e4b26_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis_3c1492aa-d823-4876-8170-9af0c70e4b26" xlink:to="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_3c1492aa-d823-4876-8170-9af0c70e4b26_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_95b60368-dac1-48c2-b6bd-f2e5deaf87f6" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis_3c1492aa-d823-4876-8170-9af0c70e4b26" xlink:to="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_95b60368-dac1-48c2-b6bd-f2e5deaf87f6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TrademarksMember_4d1d99fc-8a3b-42f4-b125-b104e8e92a8f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TrademarksMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_95b60368-dac1-48c2-b6bd-f2e5deaf87f6" xlink:to="loc_us-gaap_TrademarksMember_4d1d99fc-8a3b-42f4-b125-b104e8e92a8f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IndefinitelivedIntangibleAssetsAcquired_7941cadf-6d04-4165-a58d-a3ed4ab53452" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IndefinitelivedIntangibleAssetsAcquired"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_e203e866-eec7-404a-8303-e0890992dfe3" xlink:to="loc_us-gaap_IndefinitelivedIntangibleAssetsAcquired_7941cadf-6d04-4165-a58d-a3ed4ab53452" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinitelivedIntangibleAssetsAcquired1_e4a3d48e-0625-467a-8b7f-e0ed08cc2b44" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FinitelivedIntangibleAssetsAcquired1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_e203e866-eec7-404a-8303-e0890992dfe3" xlink:to="loc_us-gaap_FinitelivedIntangibleAssetsAcquired1_e4a3d48e-0625-467a-8b7f-e0ed08cc2b44" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife_a66b33fb-e475-4f60-9075-a0e4c1010ed2" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_e203e866-eec7-404a-8303-e0890992dfe3" xlink:to="loc_us-gaap_AcquiredFiniteLivedIntangibleAssetsWeightedAverageUsefulLife_a66b33fb-e475-4f60-9075-a0e4c1010ed2" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.gibraltar1.com/role/AcquisitionsAcquisitionRelatedCostsDetails" xlink:type="simple" xlink:href="rock-20231231.xsd#AcquisitionsAcquisitionRelatedCostsDetails"/>
  <link:definitionLink xlink:role="http://www.gibraltar1.com/role/AcquisitionsAcquisitionRelatedCostsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessAcquisitionLineItems_330db3e6-ac60-445c-a767-71d45ba403eb" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessAcquisitionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_a3a7042c-e0a1-4887-8b36-3ff5eea004ac" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_330db3e6-ac60-445c-a767-71d45ba403eb" xlink:to="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_a3a7042c-e0a1-4887-8b36-3ff5eea004ac" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationAxis_9ccce2c9-577b-4ff4-a6a1-c4a8ae849dda" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeStatementLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfBusinessAcquisitionsByAcquisitionTable_a3a7042c-e0a1-4887-8b36-3ff5eea004ac" xlink:to="loc_us-gaap_IncomeStatementLocationAxis_9ccce2c9-577b-4ff4-a6a1-c4a8ae849dda" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_9ccce2c9-577b-4ff4-a6a1-c4a8ae849dda_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_9ccce2c9-577b-4ff4-a6a1-c4a8ae849dda" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_9ccce2c9-577b-4ff4-a6a1-c4a8ae849dda_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain_3a1224f9-bf42-4bf0-be56-9c25c691364b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeStatementLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementLocationAxis_9ccce2c9-577b-4ff4-a6a1-c4a8ae849dda" xlink:to="loc_us-gaap_IncomeStatementLocationDomain_3a1224f9-bf42-4bf0-be56-9c25c691364b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostOfSalesMember_181442bb-9b30-4076-a3f3-5e4386faadab" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CostOfSalesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_3a1224f9-bf42-4bf0-be56-9c25c691364b" xlink:to="loc_us-gaap_CostOfSalesMember_181442bb-9b30-4076-a3f3-5e4386faadab" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SellingGeneralAndAdministrativeExpensesMember_9e01b230-6335-4418-8a5b-a7dff2e3a97f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SellingGeneralAndAdministrativeExpensesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementLocationDomain_3a1224f9-bf42-4bf0-be56-9c25c691364b" xlink:to="loc_us-gaap_SellingGeneralAndAdministrativeExpensesMember_9e01b230-6335-4418-8a5b-a7dff2e3a97f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessCombinationAcquisitionRelatedCosts_88255124-d07d-48ea-8324-3a5928936b35" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessCombinationAcquisitionRelatedCosts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BusinessAcquisitionLineItems_330db3e6-ac60-445c-a767-71d45ba403eb" xlink:to="loc_us-gaap_BusinessCombinationAcquisitionRelatedCosts_88255124-d07d-48ea-8324-3a5928936b35" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.gibraltar1.com/role/GoodwillandRelatedIntangibleAssetsScheduleofChangesinCarryingAmountofGoodwillDetails" xlink:type="simple" xlink:href="rock-20231231.xsd#GoodwillandRelatedIntangibleAssetsScheduleofChangesinCarryingAmountofGoodwillDetails"/>
  <link:definitionLink xlink:role="http://www.gibraltar1.com/role/GoodwillandRelatedIntangibleAssetsScheduleofChangesinCarryingAmountofGoodwillDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillLineItems_870c2e13-5ed3-499c-8af8-6b134fb95475" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_GoodwillLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfGoodwillTable_29e61014-3b9e-425f-b1f7-de0d14c14744" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfGoodwillTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_GoodwillLineItems_870c2e13-5ed3-499c-8af8-6b134fb95475" xlink:to="loc_us-gaap_ScheduleOfGoodwillTable_29e61014-3b9e-425f-b1f7-de0d14c14744" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_01997d10-8ef7-4089-8095-1fea62a24e08" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfGoodwillTable_29e61014-3b9e-425f-b1f7-de0d14c14744" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_01997d10-8ef7-4089-8095-1fea62a24e08" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_01997d10-8ef7-4089-8095-1fea62a24e08_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_01997d10-8ef7-4089-8095-1fea62a24e08" xlink:to="loc_us-gaap_SegmentDomain_01997d10-8ef7-4089-8095-1fea62a24e08_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_a1025cda-9f9b-40c0-9064-20de22e42d07" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_01997d10-8ef7-4089-8095-1fea62a24e08" xlink:to="loc_us-gaap_SegmentDomain_a1025cda-9f9b-40c0-9064-20de22e42d07" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_RenewablesMember_91fc166c-4c51-4470-a178-420f0a9395df" xlink:href="rock-20231231.xsd#rock_RenewablesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_a1025cda-9f9b-40c0-9064-20de22e42d07" xlink:to="loc_rock_RenewablesMember_91fc166c-4c51-4470-a178-420f0a9395df" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_ResidentialMember_78a59728-85c8-4f12-bf58-014efbf704e5" xlink:href="rock-20231231.xsd#rock_ResidentialMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_a1025cda-9f9b-40c0-9064-20de22e42d07" xlink:to="loc_rock_ResidentialMember_78a59728-85c8-4f12-bf58-014efbf704e5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_AgtechMember_6935211b-7293-4d9c-91f5-53168ab5067c" xlink:href="rock-20231231.xsd#rock_AgtechMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_a1025cda-9f9b-40c0-9064-20de22e42d07" xlink:to="loc_rock_AgtechMember_6935211b-7293-4d9c-91f5-53168ab5067c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_InfrastructureMember_80baeeb8-9cbc-43e2-b283-d300491b5da9" xlink:href="rock-20231231.xsd#rock_InfrastructureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_a1025cda-9f9b-40c0-9064-20de22e42d07" xlink:to="loc_rock_InfrastructureMember_80baeeb8-9cbc-43e2-b283-d300491b5da9" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillRollForward_73904c31-d657-4c3a-aeae-a9c5dfcad9b2" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_GoodwillRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillLineItems_870c2e13-5ed3-499c-8af8-6b134fb95475" xlink:to="loc_us-gaap_GoodwillRollForward_73904c31-d657-4c3a-aeae-a9c5dfcad9b2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Goodwill_1d56adc5-bdbf-40bf-9660-89b6ee2cf4c1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_Goodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillRollForward_73904c31-d657-4c3a-aeae-a9c5dfcad9b2" xlink:to="loc_us-gaap_Goodwill_1d56adc5-bdbf-40bf-9660-89b6ee2cf4c1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillAcquiredDuringPeriod_1630e08a-7afe-465c-9dd9-66b1bd6ce680" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_GoodwillAcquiredDuringPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillRollForward_73904c31-d657-4c3a-aeae-a9c5dfcad9b2" xlink:to="loc_us-gaap_GoodwillAcquiredDuringPeriod_1630e08a-7afe-465c-9dd9-66b1bd6ce680" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillPurchaseAccountingAdjustments_de39d75d-9eb2-493c-a171-3ad3c803a708" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_GoodwillPurchaseAccountingAdjustments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillRollForward_73904c31-d657-4c3a-aeae-a9c5dfcad9b2" xlink:to="loc_us-gaap_GoodwillPurchaseAccountingAdjustments_de39d75d-9eb2-493c-a171-3ad3c803a708" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillForeignCurrencyTranslationGainLoss_fe7b146c-1bac-4b17-9d6d-609c90b74aff" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_GoodwillForeignCurrencyTranslationGainLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillRollForward_73904c31-d657-4c3a-aeae-a9c5dfcad9b2" xlink:to="loc_us-gaap_GoodwillForeignCurrencyTranslationGainLoss_fe7b146c-1bac-4b17-9d6d-609c90b74aff" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillWrittenOffRelatedToSaleOfBusinessUnit_f8c2476f-26b3-4003-b727-a29a0f1b0e76" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_GoodwillWrittenOffRelatedToSaleOfBusinessUnit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillRollForward_73904c31-d657-4c3a-aeae-a9c5dfcad9b2" xlink:to="loc_us-gaap_GoodwillWrittenOffRelatedToSaleOfBusinessUnit_f8c2476f-26b3-4003-b727-a29a0f1b0e76" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Goodwill_7ca0091a-11b3-43c5-a691-ef1c65d89f12" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_Goodwill"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.gibraltar1.com/role/GoodwillandRelatedIntangibleAssetsNarrativeDetails" xlink:type="simple" xlink:href="rock-20231231.xsd#GoodwillandRelatedIntangibleAssetsNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.gibraltar1.com/role/GoodwillandRelatedIntangibleAssetsNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillLineItems_53b386c1-48a5-4750-a018-2f058716afdd" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_GoodwillLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfGoodwillTable_86ef363e-8f39-4bea-a8b5-54814a02c83e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfGoodwillTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_GoodwillLineItems_53b386c1-48a5-4750-a018-2f058716afdd" xlink:to="loc_us-gaap_ScheduleOfGoodwillTable_86ef363e-8f39-4bea-a8b5-54814a02c83e" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis_8bf7278a-b874-4d18-b8a2-5329efd7b1a5" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfGoodwillTable_86ef363e-8f39-4bea-a8b5-54814a02c83e" xlink:to="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis_8bf7278a-b874-4d18-b8a2-5329efd7b1a5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_8bf7278a-b874-4d18-b8a2-5329efd7b1a5_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis_8bf7278a-b874-4d18-b8a2-5329efd7b1a5" xlink:to="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_8bf7278a-b874-4d18-b8a2-5329efd7b1a5_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_cc5033b4-ec4e-4728-962c-d8f184013880" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis_8bf7278a-b874-4d18-b8a2-5329efd7b1a5" xlink:to="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_cc5033b4-ec4e-4728-962c-d8f184013880" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TrademarksMember_475189c9-466b-4166-9142-b501fe10fd3c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TrademarksMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_cc5033b4-ec4e-4728-962c-d8f184013880" xlink:to="loc_us-gaap_TrademarksMember_475189c9-466b-4166-9142-b501fe10fd3c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillImpairedAccumulatedImpairmentLoss_c7759c7b-ce91-4475-b2c8-7e602d80b98c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_GoodwillImpairedAccumulatedImpairmentLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillLineItems_53b386c1-48a5-4750-a018-2f058716afdd" xlink:to="loc_us-gaap_GoodwillImpairedAccumulatedImpairmentLoss_c7759c7b-ce91-4475-b2c8-7e602d80b98c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillImpairmentLoss_bd9396de-eb64-4092-a7f2-cc0cd160dcfe" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_GoodwillImpairmentLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillLineItems_53b386c1-48a5-4750-a018-2f058716afdd" xlink:to="loc_us-gaap_GoodwillImpairmentLoss_bd9396de-eb64-4092-a7f2-cc0cd160dcfe" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ImpairmentOfIntangibleAssetsIndefinitelivedExcludingGoodwill_01a653e3-dc5d-496a-a589-a278a2c30d51" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ImpairmentOfIntangibleAssetsIndefinitelivedExcludingGoodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillLineItems_53b386c1-48a5-4750-a018-2f058716afdd" xlink:to="loc_us-gaap_ImpairmentOfIntangibleAssetsIndefinitelivedExcludingGoodwill_01a653e3-dc5d-496a-a589-a278a2c30d51" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_ReportingUnitCarryingAmountInExcessOfFairValueNumberOfReportingUnits_a813caee-7b4b-4753-8200-f13d6fd08686" xlink:href="rock-20231231.xsd#rock_ReportingUnitCarryingAmountInExcessOfFairValueNumberOfReportingUnits"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillLineItems_53b386c1-48a5-4750-a018-2f058716afdd" xlink:to="loc_rock_ReportingUnitCarryingAmountInExcessOfFairValueNumberOfReportingUnits_a813caee-7b4b-4753-8200-f13d6fd08686" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ImpairmentOfIntangibleAssetIndefiniteLivedExcludingGoodwillStatementOfIncomeOrComprehensiveIncomeExtensibleEnumeration_8e54d438-196f-42b6-a743-f92503fb72ad" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ImpairmentOfIntangibleAssetIndefiniteLivedExcludingGoodwillStatementOfIncomeOrComprehensiveIncomeExtensibleEnumeration"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillLineItems_53b386c1-48a5-4750-a018-2f058716afdd" xlink:to="loc_us-gaap_ImpairmentOfIntangibleAssetIndefiniteLivedExcludingGoodwillStatementOfIncomeOrComprehensiveIncomeExtensibleEnumeration_8e54d438-196f-42b6-a743-f92503fb72ad" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NumberOfReportingUnits_97036da0-07e1-41b7-949e-34a654ab264f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_NumberOfReportingUnits"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_GoodwillLineItems_53b386c1-48a5-4750-a018-2f058716afdd" xlink:to="loc_us-gaap_NumberOfReportingUnits_97036da0-07e1-41b7-949e-34a654ab264f" xlink:type="arc" order="5"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.gibraltar1.com/role/GoodwillandRelatedIntangibleAssetsScheduleofAcquiredIntangibleAssetsDetails" xlink:type="simple" xlink:href="rock-20231231.xsd#GoodwillandRelatedIntangibleAssetsScheduleofAcquiredIntangibleAssetsDetails"/>
  <link:definitionLink xlink:role="http://www.gibraltar1.com/role/GoodwillandRelatedIntangibleAssetsScheduleofAcquiredIntangibleAssetsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_04ddb2c0-711f-4e4a-a251-c8a5121d3f9f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_e23e29dc-6363-4b99-a581-f029b877df75" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_04ddb2c0-711f-4e4a-a251-c8a5121d3f9f" xlink:to="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_e23e29dc-6363-4b99-a581-f029b877df75" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis_ca3179e1-2210-4bde-b58d-6d3455cbc6ee" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_e23e29dc-6363-4b99-a581-f029b877df75" xlink:to="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis_ca3179e1-2210-4bde-b58d-6d3455cbc6ee" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_ca3179e1-2210-4bde-b58d-6d3455cbc6ee_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis_ca3179e1-2210-4bde-b58d-6d3455cbc6ee" xlink:to="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_ca3179e1-2210-4bde-b58d-6d3455cbc6ee_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_14916022-2567-411b-bb8c-848d754fbe6a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis_ca3179e1-2210-4bde-b58d-6d3455cbc6ee" xlink:to="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_14916022-2567-411b-bb8c-848d754fbe6a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TrademarksMember_14286719-9adb-463d-95c6-de4b81064d0d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TrademarksMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_14916022-2567-411b-bb8c-848d754fbe6a" xlink:to="loc_us-gaap_TrademarksMember_14286719-9adb-463d-95c6-de4b81064d0d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_a7239bfb-f343-4966-9ab1-42d0c80c9d81" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_e23e29dc-6363-4b99-a581-f029b877df75" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_a7239bfb-f343-4966-9ab1-42d0c80c9d81" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_a7239bfb-f343-4966-9ab1-42d0c80c9d81_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_a7239bfb-f343-4966-9ab1-42d0c80c9d81" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_a7239bfb-f343-4966-9ab1-42d0c80c9d81_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_3339478b-04ed-4987-b99b-7f65e1c97447" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis_a7239bfb-f343-4966-9ab1-42d0c80c9d81" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_3339478b-04ed-4987-b99b-7f65e1c97447" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TrademarksMember_3c944b58-7114-467a-b0e3-2784c5995856" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TrademarksMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_3339478b-04ed-4987-b99b-7f65e1c97447" xlink:to="loc_us-gaap_TrademarksMember_3c944b58-7114-467a-b0e3-2784c5995856" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnpatentedTechnologyMember_edbaa605-c598-4475-be50-b5c9ef1fd704" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_UnpatentedTechnologyMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_3339478b-04ed-4987-b99b-7f65e1c97447" xlink:to="loc_us-gaap_UnpatentedTechnologyMember_edbaa605-c598-4475-be50-b5c9ef1fd704" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CustomerRelationshipsMember_d86d0d4e-11b8-4ded-b3f0-20fa948581c0" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CustomerRelationshipsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_3339478b-04ed-4987-b99b-7f65e1c97447" xlink:to="loc_us-gaap_CustomerRelationshipsMember_d86d0d4e-11b8-4ded-b3f0-20fa948581c0" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NoncompeteAgreementsMember_04df2b4b-25a5-4923-b39f-44869e826f62" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_NoncompeteAgreementsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsMajorClassNameDomain_3339478b-04ed-4987-b99b-7f65e1c97447" xlink:to="loc_us-gaap_NoncompeteAgreementsMember_04df2b4b-25a5-4923-b39f-44869e826f62" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IndefiniteLivedIntangibleAssetsExcludingGoodwill_3a22e8db-8bc0-494e-8992-11f5375c7972" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IndefiniteLivedIntangibleAssetsExcludingGoodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_04ddb2c0-711f-4e4a-a251-c8a5121d3f9f" xlink:to="loc_us-gaap_IndefiniteLivedIntangibleAssetsExcludingGoodwill_3a22e8db-8bc0-494e-8992-11f5375c7972" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsGross_6f5cca89-fec0-4e73-8f53-6f3e12820c89" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_04ddb2c0-711f-4e4a-a251-c8a5121d3f9f" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsGross_6f5cca89-fec0-4e73-8f53-6f3e12820c89" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_AcquiredIntangibleAssetsTotal_08bbb2d1-bee7-46c6-97bf-7ae83ff4f2e2" xlink:href="rock-20231231.xsd#rock_AcquiredIntangibleAssetsTotal"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_04ddb2c0-711f-4e4a-a251-c8a5121d3f9f" xlink:to="loc_rock_AcquiredIntangibleAssetsTotal_08bbb2d1-bee7-46c6-97bf-7ae83ff4f2e2" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_IndefiniteLivedAccumulatedAmortization_5b062dc0-d2b7-4f41-8bd4-48ff68151b6c" xlink:href="rock-20231231.xsd#rock_IndefiniteLivedAccumulatedAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_04ddb2c0-711f-4e4a-a251-c8a5121d3f9f" xlink:to="loc_rock_IndefiniteLivedAccumulatedAmortization_5b062dc0-d2b7-4f41-8bd4-48ff68151b6c" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_ac05ed54-d075-411a-9cdd-2a0f5ebbcf39" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_04ddb2c0-711f-4e4a-a251-c8a5121d3f9f" xlink:to="loc_us-gaap_FiniteLivedIntangibleAssetsAccumulatedAmortization_ac05ed54-d075-411a-9cdd-2a0f5ebbcf39" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_TotalAcquiredIntangibleAssetsAccumulatedAmortization_5371ae66-d157-472d-8e02-056df142250a" xlink:href="rock-20231231.xsd#rock_TotalAcquiredIntangibleAssetsAccumulatedAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_04ddb2c0-711f-4e4a-a251-c8a5121d3f9f" xlink:to="loc_rock_TotalAcquiredIntangibleAssetsAccumulatedAmortization_5371ae66-d157-472d-8e02-056df142250a" xlink:type="arc" order="5"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.gibraltar1.com/role/GoodwillandRelatedIntangibleAssetsScheduleofImpairmentChargesDetails" xlink:type="simple" xlink:href="rock-20231231.xsd#GoodwillandRelatedIntangibleAssetsScheduleofImpairmentChargesDetails"/>
  <link:definitionLink xlink:role="http://www.gibraltar1.com/role/GoodwillandRelatedIntangibleAssetsScheduleofImpairmentChargesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_8e9c6f16-20e8-44ff-88dc-759b53c875ac" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_FiniteLivedIntangibleAssetsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_55e9724c-dcff-44c1-820b-39f6a002fb35" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_8e9c6f16-20e8-44ff-88dc-759b53c875ac" xlink:to="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_55e9724c-dcff-44c1-820b-39f6a002fb35" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_16c6ab47-2b43-4b0b-9fb8-dac5810ab3e3" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_55e9724c-dcff-44c1-820b-39f6a002fb35" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_16c6ab47-2b43-4b0b-9fb8-dac5810ab3e3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_16c6ab47-2b43-4b0b-9fb8-dac5810ab3e3_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_16c6ab47-2b43-4b0b-9fb8-dac5810ab3e3" xlink:to="loc_us-gaap_SegmentDomain_16c6ab47-2b43-4b0b-9fb8-dac5810ab3e3_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_cf51b63f-4b64-4334-86ce-e1ff2d836f66" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_16c6ab47-2b43-4b0b-9fb8-dac5810ab3e3" xlink:to="loc_us-gaap_SegmentDomain_cf51b63f-4b64-4334-86ce-e1ff2d836f66" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_RenewablesMember_03d6cd9a-ca97-4830-8d8e-88c18eef2a92" xlink:href="rock-20231231.xsd#rock_RenewablesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_cf51b63f-4b64-4334-86ce-e1ff2d836f66" xlink:to="loc_rock_RenewablesMember_03d6cd9a-ca97-4830-8d8e-88c18eef2a92" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_ResidentialMember_8399befb-366f-4ee4-9b97-31627c6289a6" xlink:href="rock-20231231.xsd#rock_ResidentialMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_cf51b63f-4b64-4334-86ce-e1ff2d836f66" xlink:to="loc_rock_ResidentialMember_8399befb-366f-4ee4-9b97-31627c6289a6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_InfrastructureMember_82173892-599c-4026-92e3-c74ca4b78263" xlink:href="rock-20231231.xsd#rock_InfrastructureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_cf51b63f-4b64-4334-86ce-e1ff2d836f66" xlink:to="loc_rock_InfrastructureMember_82173892-599c-4026-92e3-c74ca4b78263" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis_7eb2e820-29fb-43de-b8e1-293b477d4fa2" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfFiniteLivedIntangibleAssetsTable_55e9724c-dcff-44c1-820b-39f6a002fb35" xlink:to="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis_7eb2e820-29fb-43de-b8e1-293b477d4fa2" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_7eb2e820-29fb-43de-b8e1-293b477d4fa2_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis_7eb2e820-29fb-43de-b8e1-293b477d4fa2" xlink:to="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_7eb2e820-29fb-43de-b8e1-293b477d4fa2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_00cc2be2-2ae9-447f-94d5-e8a349baf401" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis_7eb2e820-29fb-43de-b8e1-293b477d4fa2" xlink:to="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_00cc2be2-2ae9-447f-94d5-e8a349baf401" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TrademarksMember_32d02fdc-c409-42bc-b956-c80abcd83794" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TrademarksMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IndefiniteLivedIntangibleAssetsMajorClassNameDomain_00cc2be2-2ae9-447f-94d5-e8a349baf401" xlink:to="loc_us-gaap_TrademarksMember_32d02fdc-c409-42bc-b956-c80abcd83794" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ImpairmentOfIntangibleAssetsIndefinitelivedExcludingGoodwill_601e1d21-db83-43b8-b4da-0d447ed9770f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ImpairmentOfIntangibleAssetsIndefinitelivedExcludingGoodwill"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_FiniteLivedIntangibleAssetsLineItems_8e9c6f16-20e8-44ff-88dc-759b53c875ac" xlink:to="loc_us-gaap_ImpairmentOfIntangibleAssetsIndefinitelivedExcludingGoodwill_601e1d21-db83-43b8-b4da-0d447ed9770f" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.gibraltar1.com/role/DebtNarrativeDetails" xlink:type="simple" xlink:href="rock-20231231.xsd#DebtNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.gibraltar1.com/role/DebtNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentLineItems_532736c9-57a8-4584-8e3e-273b5f3366c6" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentTable_c8293c2b-5579-4f6d-b937-23bd67d9a03c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DebtInstrumentLineItems_532736c9-57a8-4584-8e3e-273b5f3366c6" xlink:to="loc_us-gaap_DebtInstrumentTable_c8293c2b-5579-4f6d-b937-23bd67d9a03c" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeAxis_6c7999e8-69e4-4b1a-b62d-f57ed2240116" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongtermDebtTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_c8293c2b-5579-4f6d-b937-23bd67d9a03c" xlink:to="loc_us-gaap_LongtermDebtTypeAxis_6c7999e8-69e4-4b1a-b62d-f57ed2240116" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_6c7999e8-69e4-4b1a-b62d-f57ed2240116_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_6c7999e8-69e4-4b1a-b62d-f57ed2240116" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_6c7999e8-69e4-4b1a-b62d-f57ed2240116_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongtermDebtTypeDomain_d7f20e8e-d057-4c26-aa4c-697ce88c9d6b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongtermDebtTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_LongtermDebtTypeAxis_6c7999e8-69e4-4b1a-b62d-f57ed2240116" xlink:to="loc_us-gaap_LongtermDebtTypeDomain_d7f20e8e-d057-4c26-aa4c-697ce88c9d6b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditMember_93083680-5647-4665-8120-ccc005137a27" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LineOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_d7f20e8e-d057-4c26-aa4c-697ce88c9d6b" xlink:to="loc_us-gaap_LineOfCreditMember_93083680-5647-4665-8120-ccc005137a27" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MediumTermNotesMember_6973c467-e4b7-490e-a38a-50dc8060b8c1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_MediumTermNotesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LongtermDebtTypeDomain_d7f20e8e-d057-4c26-aa4c-697ce88c9d6b" xlink:to="loc_us-gaap_MediumTermNotesMember_6973c467-e4b7-490e-a38a-50dc8060b8c1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_8389f0ca-2945-420a-af7c-b9655e7f74d7" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_c8293c2b-5579-4f6d-b937-23bd67d9a03c" xlink:to="loc_us-gaap_DebtInstrumentAxis_8389f0ca-2945-420a-af7c-b9655e7f74d7" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_8389f0ca-2945-420a-af7c-b9655e7f74d7_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_8389f0ca-2945-420a-af7c-b9655e7f74d7" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_8389f0ca-2945-420a-af7c-b9655e7f74d7_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_3ea5a241-1d7a-488e-b399-297caf16e580" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_8389f0ca-2945-420a-af7c-b9655e7f74d7" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_3ea5a241-1d7a-488e-b399-297caf16e580" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_A2022SeniorCreditAgreementMember_d04bd859-fdaf-407a-9fd0-0b0e5fca0186" xlink:href="rock-20231231.xsd#rock_A2022SeniorCreditAgreementMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_3ea5a241-1d7a-488e-b399-297caf16e580" xlink:to="loc_rock_A2022SeniorCreditAgreementMember_d04bd859-fdaf-407a-9fd0-0b0e5fca0186" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_A2019SeniorCreditAgreementMember_9109f297-87a4-4549-b0d1-610c68ce6634" xlink:href="rock-20231231.xsd#rock_A2019SeniorCreditAgreementMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_3ea5a241-1d7a-488e-b399-297caf16e580" xlink:to="loc_rock_A2019SeniorCreditAgreementMember_9109f297-87a4-4549-b0d1-610c68ce6634" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_SeniorCreditAgreementMember_5eae38ee-486d-4694-9025-7f5b127e8de7" xlink:href="rock-20231231.xsd#rock_SeniorCreditAgreementMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_3ea5a241-1d7a-488e-b399-297caf16e580" xlink:to="loc_rock_SeniorCreditAgreementMember_5eae38ee-486d-4694-9025-7f5b127e8de7" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityAxis_a714c776-e0a1-4ad0-a7d3-fb9ece048529" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CreditFacilityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_c8293c2b-5579-4f6d-b937-23bd67d9a03c" xlink:to="loc_us-gaap_CreditFacilityAxis_a714c776-e0a1-4ad0-a7d3-fb9ece048529" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_a714c776-e0a1-4ad0-a7d3-fb9ece048529_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CreditFacilityAxis_a714c776-e0a1-4ad0-a7d3-fb9ece048529" xlink:to="loc_us-gaap_CreditFacilityDomain_a714c776-e0a1-4ad0-a7d3-fb9ece048529_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_8105bbe5-ecf3-4488-b5f6-e5f9615ec5e6" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CreditFacilityAxis_a714c776-e0a1-4ad0-a7d3-fb9ece048529" xlink:to="loc_us-gaap_CreditFacilityDomain_8105bbe5-ecf3-4488-b5f6-e5f9615ec5e6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StandbyLettersOfCreditMember_2382edb9-89e6-4a43-8a33-57b6ca559e1a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StandbyLettersOfCreditMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_8105bbe5-ecf3-4488-b5f6-e5f9615ec5e6" xlink:to="loc_us-gaap_StandbyLettersOfCreditMember_2382edb9-89e6-4a43-8a33-57b6ca559e1a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevolvingCreditFacilityMember_1b634b0b-ffea-41d6-b07f-20e5843b2c2c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RevolvingCreditFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_8105bbe5-ecf3-4488-b5f6-e5f9615ec5e6" xlink:to="loc_us-gaap_RevolvingCreditFacilityMember_1b634b0b-ffea-41d6-b07f-20e5843b2c2c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_7081ef67-66f0-4781-9119-139b6ef1e5a7" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_c8293c2b-5579-4f6d-b937-23bd67d9a03c" xlink:to="loc_srt_RangeAxis_7081ef67-66f0-4781-9119-139b6ef1e5a7" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_7081ef67-66f0-4781-9119-139b6ef1e5a7_default" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_7081ef67-66f0-4781-9119-139b6ef1e5a7" xlink:to="loc_srt_RangeMember_7081ef67-66f0-4781-9119-139b6ef1e5a7_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_8c34c007-69dd-43e8-bc12-0e622386e3a8" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_7081ef67-66f0-4781-9119-139b6ef1e5a7" xlink:to="loc_srt_RangeMember_8c34c007-69dd-43e8-bc12-0e622386e3a8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_908c322a-e8d4-4b02-9353-e01c04d3be15" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_8c34c007-69dd-43e8-bc12-0e622386e3a8" xlink:to="loc_srt_MinimumMember_908c322a-e8d4-4b02-9353-e01c04d3be15" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_ed0912a8-f144-4191-9fb6-c06cb43f6ff7" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_8c34c007-69dd-43e8-bc12-0e622386e3a8" xlink:to="loc_srt_MaximumMember_ed0912a8-f144-4191-9fb6-c06cb43f6ff7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateAxis_13bb8889-31ac-475d-89ca-6c6011ccc371" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_VariableRateAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_c8293c2b-5579-4f6d-b937-23bd67d9a03c" xlink:to="loc_us-gaap_VariableRateAxis_13bb8889-31ac-475d-89ca-6c6011ccc371" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateDomain_13bb8889-31ac-475d-89ca-6c6011ccc371_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_VariableRateDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_VariableRateAxis_13bb8889-31ac-475d-89ca-6c6011ccc371" xlink:to="loc_us-gaap_VariableRateDomain_13bb8889-31ac-475d-89ca-6c6011ccc371_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_VariableRateDomain_f0e0b86e-c99f-48b9-899f-0db37da34658" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_VariableRateDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_VariableRateAxis_13bb8889-31ac-475d-89ca-6c6011ccc371" xlink:to="loc_us-gaap_VariableRateDomain_f0e0b86e-c99f-48b9-899f-0db37da34658" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BaseRateMember_534fcad8-5031-47bf-8a3c-6ad6801479b3" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BaseRateMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableRateDomain_f0e0b86e-c99f-48b9-899f-0db37da34658" xlink:to="loc_us-gaap_BaseRateMember_534fcad8-5031-47bf-8a3c-6ad6801479b3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_SecuredOvernightFinancingRateSOFRMember_0d0c240d-4b10-41c5-b817-7c186698c405" xlink:href="rock-20231231.xsd#rock_SecuredOvernightFinancingRateSOFRMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableRateDomain_f0e0b86e-c99f-48b9-899f-0db37da34658" xlink:to="loc_rock_SecuredOvernightFinancingRateSOFRMember_0d0c240d-4b10-41c5-b817-7c186698c405" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_LondonInterbankOfferedRateLIBOR1Member_3d06495e-3acd-4481-9f6f-b7e5ee36d032" xlink:href="rock-20231231.xsd#rock_LondonInterbankOfferedRateLIBOR1Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_VariableRateDomain_f0e0b86e-c99f-48b9-899f-0db37da34658" xlink:to="loc_rock_LondonInterbankOfferedRateLIBOR1Member_3d06495e-3acd-4481-9f6f-b7e5ee36d032" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_DebtInstrumentApplicableRatePeriodAxis_6ae585ac-8c4b-4dfd-90c6-bcc16b09941e" xlink:href="rock-20231231.xsd#rock_DebtInstrumentApplicableRatePeriodAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DebtInstrumentTable_c8293c2b-5579-4f6d-b937-23bd67d9a03c" xlink:to="loc_rock_DebtInstrumentApplicableRatePeriodAxis_6ae585ac-8c4b-4dfd-90c6-bcc16b09941e" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_DebtInstrumentApplicableRatePeriodDomain_6ae585ac-8c4b-4dfd-90c6-bcc16b09941e_default" xlink:href="rock-20231231.xsd#rock_DebtInstrumentApplicableRatePeriodDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_rock_DebtInstrumentApplicableRatePeriodAxis_6ae585ac-8c4b-4dfd-90c6-bcc16b09941e" xlink:to="loc_rock_DebtInstrumentApplicableRatePeriodDomain_6ae585ac-8c4b-4dfd-90c6-bcc16b09941e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_DebtInstrumentApplicableRatePeriodDomain_016f60f2-a665-405b-ba8f-1a784ba168c9" xlink:href="rock-20231231.xsd#rock_DebtInstrumentApplicableRatePeriodDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_rock_DebtInstrumentApplicableRatePeriodAxis_6ae585ac-8c4b-4dfd-90c6-bcc16b09941e" xlink:to="loc_rock_DebtInstrumentApplicableRatePeriodDomain_016f60f2-a665-405b-ba8f-1a784ba168c9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_ApplicableRatePeriod1Member_aa0e1509-2cc2-4037-895a-643fdb7cfd37" xlink:href="rock-20231231.xsd#rock_ApplicableRatePeriod1Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_rock_DebtInstrumentApplicableRatePeriodDomain_016f60f2-a665-405b-ba8f-1a784ba168c9" xlink:to="loc_rock_ApplicableRatePeriod1Member_aa0e1509-2cc2-4037-895a-643fdb7cfd37" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_ApplicableRatePeriod2Member_c2e2ff5f-429d-439a-a4e5-808649258f5e" xlink:href="rock-20231231.xsd#rock_ApplicableRatePeriod2Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_rock_DebtInstrumentApplicableRatePeriodDomain_016f60f2-a665-405b-ba8f-1a784ba168c9" xlink:to="loc_rock_ApplicableRatePeriod2Member_c2e2ff5f-429d-439a-a4e5-808649258f5e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity_bab648f1-80d6-4102-89f0-70f82a1b8df6" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_532736c9-57a8-4584-8e3e-273b5f3366c6" xlink:to="loc_us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity_bab648f1-80d6-4102-89f0-70f82a1b8df6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_1c24225a-b0be-4414-82cf-b84899d284f8" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_532736c9-57a8-4584-8e3e-273b5f3366c6" xlink:to="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_1c24225a-b0be-4414-82cf-b84899d284f8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentFaceAmount_8f8f1d2f-883f-4e23-92cd-c9ef51e0d0e9" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentFaceAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_532736c9-57a8-4584-8e3e-273b5f3366c6" xlink:to="loc_us-gaap_DebtInstrumentFaceAmount_8f8f1d2f-883f-4e23-92cd-c9ef51e0d0e9" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_DebtInstrumentNumberOfDebtCovenants_a11d6e87-6b4b-4d0a-b4f7-11bf0606ff56" xlink:href="rock-20231231.xsd#rock_DebtInstrumentNumberOfDebtCovenants"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_532736c9-57a8-4584-8e3e-273b5f3366c6" xlink:to="loc_rock_DebtInstrumentNumberOfDebtCovenants_a11d6e87-6b4b-4d0a-b4f7-11bf0606ff56" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_4b9c2b83-7029-472f-8467-5d15ddfca2d0" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_532736c9-57a8-4584-8e3e-273b5f3366c6" xlink:to="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_4b9c2b83-7029-472f-8467-5d15ddfca2d0" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentage_83e1f0b6-9980-436d-a814-4c6c7ee39c36" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_532736c9-57a8-4584-8e3e-273b5f3366c6" xlink:to="loc_us-gaap_LineOfCreditFacilityUnusedCapacityCommitmentFeePercentage_83e1f0b6-9980-436d-a814-4c6c7ee39c36" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebt_88c896a5-689e-4430-8f25-35c5a956a888" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongTermDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_532736c9-57a8-4584-8e3e-273b5f3366c6" xlink:to="loc_us-gaap_LongTermDebt_88c896a5-689e-4430-8f25-35c5a956a888" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_3109337a-8904-4717-bed6-ec77aa5f1fb8" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentBasisSpreadOnVariableRate1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_532736c9-57a8-4584-8e3e-273b5f3366c6" xlink:to="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate1_3109337a-8904-4717-bed6-ec77aa5f1fb8" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityCommitmentFeePercentage_67673096-4588-4d06-9424-07fcd945b744" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LineOfCreditFacilityCommitmentFeePercentage"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_532736c9-57a8-4584-8e3e-273b5f3366c6" xlink:to="loc_us-gaap_LineOfCreditFacilityCommitmentFeePercentage_67673096-4588-4d06-9424-07fcd945b744" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity_559adf1d-2f43-4b3d-b05e-6372f57d67b5" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_532736c9-57a8-4584-8e3e-273b5f3366c6" xlink:to="loc_us-gaap_LineOfCreditFacilityRemainingBorrowingCapacity_559adf1d-2f43-4b3d-b05e-6372f57d67b5" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredFinanceCostsNet_3047c5c0-0223-414a-b87c-5fdac7a3ef76" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DeferredFinanceCostsNet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_532736c9-57a8-4584-8e3e-273b5f3366c6" xlink:to="loc_us-gaap_DeferredFinanceCostsNet_3047c5c0-0223-414a-b87c-5fdac7a3ef76" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentCarryingAmount_bfb741ec-b0e3-4a00-ad6d-13de44eb6c98" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentCarryingAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentLineItems_532736c9-57a8-4584-8e3e-273b5f3366c6" xlink:to="loc_us-gaap_DebtInstrumentCarryingAmount_bfb741ec-b0e3-4a00-ad6d-13de44eb6c98" xlink:type="arc" order="11"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.gibraltar1.com/role/PensionandOtherPostretirementBenefitsScheduleofTotalExpenseforAllRetirementPlansDetails" xlink:type="simple" xlink:href="rock-20231231.xsd#PensionandOtherPostretirementBenefitsScheduleofTotalExpenseforAllRetirementPlansDetails"/>
  <link:definitionLink xlink:role="http://www.gibraltar1.com/role/PensionandOtherPostretirementBenefitsScheduleofTotalExpenseforAllRetirementPlansDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_dc5ce898-9264-4507-a8de-53a792dda2ef" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanDisclosureLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_682ea7b4-baa8-4c08-8403-01f47aa52ec3" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_dc5ce898-9264-4507-a8de-53a792dda2ef" xlink:to="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_682ea7b4-baa8-4c08-8403-01f47aa52ec3" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeAxis_91a6853f-715a-4c7c-bd0e-357d622b6ce5" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RetirementPlanTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable_682ea7b4-baa8-4c08-8403-01f47aa52ec3" xlink:to="loc_us-gaap_RetirementPlanTypeAxis_91a6853f-715a-4c7c-bd0e-357d622b6ce5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_91a6853f-715a-4c7c-bd0e-357d622b6ce5_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RetirementPlanTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_91a6853f-715a-4c7c-bd0e-357d622b6ce5" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_91a6853f-715a-4c7c-bd0e-357d622b6ce5_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_6cc43b0b-42ec-4de7-afd7-5fabcc1edc90" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RetirementPlanTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_91a6853f-715a-4c7c-bd0e-357d622b6ce5" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_6cc43b0b-42ec-4de7-afd7-5fabcc1edc90" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_A401kPlanMember_79877e42-b199-44e7-ab70-fdd3a23886cc" xlink:href="rock-20231231.xsd#rock_A401kPlanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanTypeDomain_6cc43b0b-42ec-4de7-afd7-5fabcc1edc90" xlink:to="loc_rock_A401kPlanMember_79877e42-b199-44e7-ab70-fdd3a23886cc" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PensionPlansDefinedBenefitMember_ff3fc6a6-da98-41e2-8e69-ec088c24ddd1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PensionPlansDefinedBenefitMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanTypeDomain_6cc43b0b-42ec-4de7-afd7-5fabcc1edc90" xlink:to="loc_us-gaap_PensionPlansDefinedBenefitMember_ff3fc6a6-da98-41e2-8e69-ec088c24ddd1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPostretirementHealthCoverageMember_31c75b41-c124-4084-9316-1c35bd786726" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPostretirementHealthCoverageMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanTypeDomain_6cc43b0b-42ec-4de7-afd7-5fabcc1edc90" xlink:to="loc_us-gaap_DefinedBenefitPostretirementHealthCoverageMember_31c75b41-c124-4084-9316-1c35bd786726" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PostemploymentBenefitsPeriodExpense_d8e721a9-22a4-42cd-a341-1b5812d4bca7" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PostemploymentBenefitsPeriodExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_dc5ce898-9264-4507-a8de-53a792dda2ef" xlink:to="loc_us-gaap_PostemploymentBenefitsPeriodExpense_d8e721a9-22a4-42cd-a341-1b5812d4bca7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_RetirementPlanNumberOfPlans_20fa45d0-3ba3-4917-89d5-5f78e1a0a2e1" xlink:href="rock-20231231.xsd#rock_RetirementPlanNumberOfPlans"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanDisclosureLineItems_dc5ce898-9264-4507-a8de-53a792dda2ef" xlink:to="loc_rock_RetirementPlanNumberOfPlans_20fa45d0-3ba3-4917-89d5-5f78e1a0a2e1" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.gibraltar1.com/role/PensionandOtherPostretirementBenefitsChangesintheAccumulatedPostretirementBenefitObligationDetails" xlink:type="simple" xlink:href="rock-20231231.xsd#PensionandOtherPostretirementBenefitsChangesintheAccumulatedPostretirementBenefitObligationDetails"/>
  <link:definitionLink xlink:role="http://www.gibraltar1.com/role/PensionandOtherPostretirementBenefitsChangesintheAccumulatedPostretirementBenefitObligationDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems_3d6c3304-117b-4623-bec8-d33f93267772" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansDisclosuresTable_1981fad4-5c92-450d-a338-cb51be954322" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansDisclosuresTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems_3d6c3304-117b-4623-bec8-d33f93267772" xlink:to="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansDisclosuresTable_1981fad4-5c92-450d-a338-cb51be954322" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeAxis_4bd2bc83-e628-4165-9ec1-7dd9675bcdeb" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RetirementPlanTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansDisclosuresTable_1981fad4-5c92-450d-a338-cb51be954322" xlink:to="loc_us-gaap_RetirementPlanTypeAxis_4bd2bc83-e628-4165-9ec1-7dd9675bcdeb" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_4bd2bc83-e628-4165-9ec1-7dd9675bcdeb_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RetirementPlanTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_4bd2bc83-e628-4165-9ec1-7dd9675bcdeb" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_4bd2bc83-e628-4165-9ec1-7dd9675bcdeb_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_e5bd4fef-2c1c-4ec6-bd78-ebfac37b8f2b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RetirementPlanTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_4bd2bc83-e628-4165-9ec1-7dd9675bcdeb" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_e5bd4fef-2c1c-4ec6-bd78-ebfac37b8f2b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPostretirementHealthCoverageMember_aae54d25-4d01-4324-a79b-a8b90d7f23ae" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPostretirementHealthCoverageMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanTypeDomain_e5bd4fef-2c1c-4ec6-bd78-ebfac37b8f2b" xlink:to="loc_us-gaap_DefinedBenefitPostretirementHealthCoverageMember_aae54d25-4d01-4324-a79b-a8b90d7f23ae" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanChangeInBenefitObligationRollForward_cfd846c3-65fc-4e37-8866-48594c592e2d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanChangeInBenefitObligationRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems_3d6c3304-117b-4623-bec8-d33f93267772" xlink:to="loc_us-gaap_DefinedBenefitPlanChangeInBenefitObligationRollForward_cfd846c3-65fc-4e37-8866-48594c592e2d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanBenefitObligation_ebabb646-5453-4da1-975d-5669c7f9d4dc" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanBenefitObligation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanChangeInBenefitObligationRollForward_cfd846c3-65fc-4e37-8866-48594c592e2d" xlink:to="loc_us-gaap_DefinedBenefitPlanBenefitObligation_ebabb646-5453-4da1-975d-5669c7f9d4dc" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanInterestCost_bfb7374b-c395-4b29-9992-aa55f93aeb6f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanInterestCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanChangeInBenefitObligationRollForward_cfd846c3-65fc-4e37-8866-48594c592e2d" xlink:to="loc_us-gaap_DefinedBenefitPlanInterestCost_bfb7374b-c395-4b29-9992-aa55f93aeb6f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanActuarialGainLoss_9bd7b992-d2df-430c-91a7-24da4ec754aa" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanActuarialGainLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanChangeInBenefitObligationRollForward_cfd846c3-65fc-4e37-8866-48594c592e2d" xlink:to="loc_us-gaap_DefinedBenefitPlanActuarialGainLoss_9bd7b992-d2df-430c-91a7-24da4ec754aa" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanBenefitObligationBenefitsPaid_a3efffcf-9d38-4a76-aa9e-38869ef8ade4" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanBenefitObligationBenefitsPaid"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlanChangeInBenefitObligationRollForward_cfd846c3-65fc-4e37-8866-48594c592e2d" xlink:to="loc_us-gaap_DefinedBenefitPlanBenefitObligationBenefitsPaid_a3efffcf-9d38-4a76-aa9e-38869ef8ade4" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanBenefitObligation_d64b3d5c-9bcc-4b46-832a-5eb998c0c177" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanBenefitObligation"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanFairValueOfPlanAssets_0811bc65-f0c7-48e7-96aa-689256e92a42" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanFairValueOfPlanAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems_3d6c3304-117b-4623-bec8-d33f93267772" xlink:to="loc_us-gaap_DefinedBenefitPlanFairValueOfPlanAssets_0811bc65-f0c7-48e7-96aa-689256e92a42" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanFundedStatusOfPlan_b9f2a20a-8575-4cc8-853c-fd76d8a220b1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanFundedStatusOfPlan"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems_3d6c3304-117b-4623-bec8-d33f93267772" xlink:to="loc_us-gaap_DefinedBenefitPlanFundedStatusOfPlan_b9f2a20a-8575-4cc8-853c-fd76d8a220b1" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetPriorServiceCostCreditBeforeTax_cce08e78-303b-4ef9-ba78-ec3a51a657cb" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetPriorServiceCostCreditBeforeTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems_3d6c3304-117b-4623-bec8-d33f93267772" xlink:to="loc_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetPriorServiceCostCreditBeforeTax_cce08e78-303b-4ef9-ba78-ec3a51a657cb" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetGainsLossesBeforeTax_0f87fa22-e674-4d1d-ad19-794907a0d6dd" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetGainsLossesBeforeTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems_3d6c3304-117b-4623-bec8-d33f93267772" xlink:to="loc_us-gaap_DefinedBenefitPlanAccumulatedOtherComprehensiveIncomeNetGainsLossesBeforeTax_0f87fa22-e674-4d1d-ad19-794907a0d6dd" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanAmountsRecognizedInBalanceSheet_ccb930a4-67df-4559-aa98-097454ddd9a5" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanAmountsRecognizedInBalanceSheet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems_3d6c3304-117b-4623-bec8-d33f93267772" xlink:to="loc_us-gaap_DefinedBenefitPlanAmountsRecognizedInBalanceSheet_ccb930a4-67df-4559-aa98-097454ddd9a5" xlink:type="arc" order="5"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.gibraltar1.com/role/PensionandOtherPostretirementBenefitsAmountsRecognizedintheConsolidatedFinancialStatementsDetails" xlink:type="simple" xlink:href="rock-20231231.xsd#PensionandOtherPostretirementBenefitsAmountsRecognizedintheConsolidatedFinancialStatementsDetails"/>
  <link:definitionLink xlink:role="http://www.gibraltar1.com/role/PensionandOtherPostretirementBenefitsAmountsRecognizedintheConsolidatedFinancialStatementsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems_7c663435-4e54-4c44-b87e-591e9b62c8fa" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansDisclosuresTable_7dfd1aa6-5ad9-4625-a7e4-820558f9af5d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansDisclosuresTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems_7c663435-4e54-4c44-b87e-591e9b62c8fa" xlink:to="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansDisclosuresTable_7dfd1aa6-5ad9-4625-a7e4-820558f9af5d" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeAxis_de89a9e3-1d78-43f6-b4fe-10677395e741" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RetirementPlanTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansDisclosuresTable_7dfd1aa6-5ad9-4625-a7e4-820558f9af5d" xlink:to="loc_us-gaap_RetirementPlanTypeAxis_de89a9e3-1d78-43f6-b4fe-10677395e741" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_de89a9e3-1d78-43f6-b4fe-10677395e741_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RetirementPlanTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_de89a9e3-1d78-43f6-b4fe-10677395e741" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_de89a9e3-1d78-43f6-b4fe-10677395e741_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_157ffac5-91b0-4e2c-9478-ce01472ccab3" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RetirementPlanTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_de89a9e3-1d78-43f6-b4fe-10677395e741" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_157ffac5-91b0-4e2c-9478-ce01472ccab3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPostretirementHealthCoverageMember_89057298-1d68-4069-aceb-8724501e5639" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPostretirementHealthCoverageMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanTypeDomain_157ffac5-91b0-4e2c-9478-ce01472ccab3" xlink:to="loc_us-gaap_DefinedBenefitPostretirementHealthCoverageMember_89057298-1d68-4069-aceb-8724501e5639" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PensionAndOtherPostretirementDefinedBenefitPlansCurrentLiabilities_afb4262b-3f17-4348-989e-8d7a2477fa71" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PensionAndOtherPostretirementDefinedBenefitPlansCurrentLiabilities"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems_7c663435-4e54-4c44-b87e-591e9b62c8fa" xlink:to="loc_us-gaap_PensionAndOtherPostretirementDefinedBenefitPlansCurrentLiabilities_afb4262b-3f17-4348-989e-8d7a2477fa71" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent_14366949-a5d4-4eac-b924-52a43efaffbf" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems_7c663435-4e54-4c44-b87e-591e9b62c8fa" xlink:to="loc_us-gaap_PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesNoncurrent_14366949-a5d4-4eac-b924-52a43efaffbf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanAmountsRecognizedInOtherComprehensiveIncomeLossNetGainLossBeforeTax_2b3651c2-f72f-4346-b290-884de6f5f4da" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanAmountsRecognizedInOtherComprehensiveIncomeLossNetGainLossBeforeTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems_7c663435-4e54-4c44-b87e-591e9b62c8fa" xlink:to="loc_us-gaap_DefinedBenefitPlanAmountsRecognizedInOtherComprehensiveIncomeLossNetGainLossBeforeTax_2b3651c2-f72f-4346-b290-884de6f5f4da" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanAmountsRecognizedInBalanceSheet_bfef6954-9d45-45c9-80cd-3b967ab63243" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanAmountsRecognizedInBalanceSheet"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems_7c663435-4e54-4c44-b87e-591e9b62c8fa" xlink:to="loc_us-gaap_DefinedBenefitPlanAmountsRecognizedInBalanceSheet_bfef6954-9d45-45c9-80cd-3b967ab63243" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.gibraltar1.com/role/PensionandOtherPostretirementBenefitsComponentsofNetPeriodicPostretirementBenefitCostDetails" xlink:type="simple" xlink:href="rock-20231231.xsd#PensionandOtherPostretirementBenefitsComponentsofNetPeriodicPostretirementBenefitCostDetails"/>
  <link:definitionLink xlink:role="http://www.gibraltar1.com/role/PensionandOtherPostretirementBenefitsComponentsofNetPeriodicPostretirementBenefitCostDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems_e7b9e2be-cc9e-4616-b298-6bc29cee8bb9" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_NetPeriodicPostRetirementCostTable_2d74fba7-729e-480b-bbf5-f3267d1f9800" xlink:href="rock-20231231.xsd#rock_NetPeriodicPostRetirementCostTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems_e7b9e2be-cc9e-4616-b298-6bc29cee8bb9" xlink:to="loc_rock_NetPeriodicPostRetirementCostTable_2d74fba7-729e-480b-bbf5-f3267d1f9800" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeAxis_f424e765-1ab1-45ab-85fb-d3de57ef4e91" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RetirementPlanTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_rock_NetPeriodicPostRetirementCostTable_2d74fba7-729e-480b-bbf5-f3267d1f9800" xlink:to="loc_us-gaap_RetirementPlanTypeAxis_f424e765-1ab1-45ab-85fb-d3de57ef4e91" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_f424e765-1ab1-45ab-85fb-d3de57ef4e91_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RetirementPlanTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_f424e765-1ab1-45ab-85fb-d3de57ef4e91" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_f424e765-1ab1-45ab-85fb-d3de57ef4e91_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_52d17362-51cf-4925-816a-e9b3cfde0b6a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RetirementPlanTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_f424e765-1ab1-45ab-85fb-d3de57ef4e91" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_52d17362-51cf-4925-816a-e9b3cfde0b6a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPostretirementHealthCoverageMember_cd1d21fc-483f-4dea-8f91-f6ad68319245" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPostretirementHealthCoverageMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanTypeDomain_52d17362-51cf-4925-816a-e9b3cfde0b6a" xlink:to="loc_us-gaap_DefinedBenefitPostretirementHealthCoverageMember_cd1d21fc-483f-4dea-8f91-f6ad68319245" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanInterestCost_7cd0d39c-056b-432a-bbb1-a4370ad4b8ae" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanInterestCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems_e7b9e2be-cc9e-4616-b298-6bc29cee8bb9" xlink:to="loc_us-gaap_DefinedBenefitPlanInterestCost_7cd0d39c-056b-432a-bbb1-a4370ad4b8ae" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit_728e0aba-6b9d-4697-8ddd-be281735e2c0" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems_e7b9e2be-cc9e-4616-b298-6bc29cee8bb9" xlink:to="loc_us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit_728e0aba-6b9d-4697-8ddd-be281735e2c0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses_f4f5b4a7-e85f-458a-ab14-e98f7fb2516f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems_e7b9e2be-cc9e-4616-b298-6bc29cee8bb9" xlink:to="loc_us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses_f4f5b4a7-e85f-458a-ab14-e98f7fb2516f" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost_e06328df-8206-4ebb-94c1-fc85e3cb7b9a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems_e7b9e2be-cc9e-4616-b298-6bc29cee8bb9" xlink:to="loc_us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost_e06328df-8206-4ebb-94c1-fc85e3cb7b9a" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate_52a13e4f-fe1f-4278-aa41-256460ec22d1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems_e7b9e2be-cc9e-4616-b298-6bc29cee8bb9" xlink:to="loc_us-gaap_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRate_52a13e4f-fe1f-4278-aa41-256460ec22d1" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_DefinedBenefitPlanHealthCareCostTrendRateAssumedforNextFiscalYearMedicalCostsBeforeAge65_cec75da9-60bd-489c-bfee-74e7507fa920" xlink:href="rock-20231231.xsd#rock_DefinedBenefitPlanHealthCareCostTrendRateAssumedforNextFiscalYearMedicalCostsBeforeAge65"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems_e7b9e2be-cc9e-4616-b298-6bc29cee8bb9" xlink:to="loc_rock_DefinedBenefitPlanHealthCareCostTrendRateAssumedforNextFiscalYearMedicalCostsBeforeAge65_cec75da9-60bd-489c-bfee-74e7507fa920" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_DefinedBenefitPlanHealthCareCostTrendRateAssumedforNextFiscalYearMedicalCostsAfterAge65_02c66392-57cb-4443-8033-2f3a8134be2b" xlink:href="rock-20231231.xsd#rock_DefinedBenefitPlanHealthCareCostTrendRateAssumedforNextFiscalYearMedicalCostsAfterAge65"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems_e7b9e2be-cc9e-4616-b298-6bc29cee8bb9" xlink:to="loc_rock_DefinedBenefitPlanHealthCareCostTrendRateAssumedforNextFiscalYearMedicalCostsAfterAge65_02c66392-57cb-4443-8033-2f3a8134be2b" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_DefinedBenefitPlanHealthCareCostTrendRateAssumedforNextFiscalYearPrescriptionDrugCosts_23ae3489-239d-40c6-b2db-0dacb5260429" xlink:href="rock-20231231.xsd#rock_DefinedBenefitPlanHealthCareCostTrendRateAssumedforNextFiscalYearPrescriptionDrugCosts"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems_e7b9e2be-cc9e-4616-b298-6bc29cee8bb9" xlink:to="loc_rock_DefinedBenefitPlanHealthCareCostTrendRateAssumedforNextFiscalYearPrescriptionDrugCosts_23ae3489-239d-40c6-b2db-0dacb5260429" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanUltimateHealthCareCostTrendRate1_8b19e3ff-e760-44be-b207-c0be1a71d220" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanUltimateHealthCareCostTrendRate1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems_e7b9e2be-cc9e-4616-b298-6bc29cee8bb9" xlink:to="loc_us-gaap_DefinedBenefitPlanUltimateHealthCareCostTrendRate1_8b19e3ff-e760-44be-b207-c0be1a71d220" xlink:type="arc" order="8"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.gibraltar1.com/role/PensionandOtherPostretirementBenefitsExpectedBenefitPaymentsfromthePlanDetails" xlink:type="simple" xlink:href="rock-20231231.xsd#PensionandOtherPostretirementBenefitsExpectedBenefitPaymentsfromthePlanDetails"/>
  <link:definitionLink xlink:role="http://www.gibraltar1.com/role/PensionandOtherPostretirementBenefitsExpectedBenefitPaymentsfromthePlanDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems_45cffce9-1205-4107-9349-c08c9f3ecaf2" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansDisclosuresTable_ca799bce-536b-4011-a18b-1021b62187d2" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansDisclosuresTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems_45cffce9-1205-4107-9349-c08c9f3ecaf2" xlink:to="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansDisclosuresTable_ca799bce-536b-4011-a18b-1021b62187d2" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeAxis_ae3633ae-1456-4b8d-80f4-4e0c5fb46c7c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RetirementPlanTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansDisclosuresTable_ca799bce-536b-4011-a18b-1021b62187d2" xlink:to="loc_us-gaap_RetirementPlanTypeAxis_ae3633ae-1456-4b8d-80f4-4e0c5fb46c7c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_ae3633ae-1456-4b8d-80f4-4e0c5fb46c7c_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RetirementPlanTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_ae3633ae-1456-4b8d-80f4-4e0c5fb46c7c" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_ae3633ae-1456-4b8d-80f4-4e0c5fb46c7c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeDomain_116358ce-cb2d-4f34-ad2c-7b0d33a2d064" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RetirementPlanTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RetirementPlanTypeAxis_ae3633ae-1456-4b8d-80f4-4e0c5fb46c7c" xlink:to="loc_us-gaap_RetirementPlanTypeDomain_116358ce-cb2d-4f34-ad2c-7b0d33a2d064" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPostretirementHealthCoverageMember_78972065-04f0-4187-9c04-2f80e1eca24d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPostretirementHealthCoverageMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RetirementPlanTypeDomain_116358ce-cb2d-4f34-ad2c-7b0d33a2d064" xlink:to="loc_us-gaap_DefinedBenefitPostretirementHealthCoverageMember_78972065-04f0-4187-9c04-2f80e1eca24d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsNextTwelveMonths_e4ed852b-6029-41b9-8cf1-263d103d8285" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsNextTwelveMonths"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems_45cffce9-1205-4107-9349-c08c9f3ecaf2" xlink:to="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsNextTwelveMonths_e4ed852b-6029-41b9-8cf1-263d103d8285" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearTwo_eea9bba9-5540-4141-aff6-a6433183959d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearTwo"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems_45cffce9-1205-4107-9349-c08c9f3ecaf2" xlink:to="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearTwo_eea9bba9-5540-4141-aff6-a6433183959d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearThree_004f4146-a42f-4dfd-912f-7fc3b3ceeb82" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearThree"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems_45cffce9-1205-4107-9349-c08c9f3ecaf2" xlink:to="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearThree_004f4146-a42f-4dfd-912f-7fc3b3ceeb82" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFour_62072e62-585d-44ea-a1fe-d0750364196c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFour"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems_45cffce9-1205-4107-9349-c08c9f3ecaf2" xlink:to="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFour_62072e62-585d-44ea-a1fe-d0750364196c" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFive_6f947ff4-7d5e-471a-9d37-20a099c8699f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFive"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems_45cffce9-1205-4107-9349-c08c9f3ecaf2" xlink:to="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFive_6f947ff4-7d5e-471a-9d37-20a099c8699f" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsFiveFiscalYearsThereafter_daf57f65-600f-4050-81e2-69c680e0b31c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsFiveFiscalYearsThereafter"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DefinedBenefitPlansAndOtherPostretirementBenefitPlansTableTextBlockLineItems_45cffce9-1205-4107-9349-c08c9f3ecaf2" xlink:to="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsFiveFiscalYearsThereafter_daf57f65-600f-4050-81e2-69c680e0b31c" xlink:type="arc" order="5"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.gibraltar1.com/role/AccumulatedOtherComprehensiveLossIncomeDetails" xlink:type="simple" xlink:href="rock-20231231.xsd#AccumulatedOtherComprehensiveLossIncomeDetails"/>
  <link:definitionLink xlink:role="http://www.gibraltar1.com/role/AccumulatedOtherComprehensiveLossIncomeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_67e5bd9b-e340-4f4d-a399-881bd611ee24" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_f37f671d-d9a8-416c-92db-acd7c25d81a9" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_67e5bd9b-e340-4f4d-a399-881bd611ee24" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_f37f671d-d9a8-416c-92db-acd7c25d81a9" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_d6273500-010d-498f-a179-a6cea4f7d325" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossTable_f37f671d-d9a8-416c-92db-acd7c25d81a9" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_d6273500-010d-498f-a179-a6cea4f7d325" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_d6273500-010d-498f-a179-a6cea4f7d325_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_d6273500-010d-498f-a179-a6cea4f7d325" xlink:to="loc_us-gaap_EquityComponentDomain_d6273500-010d-498f-a179-a6cea4f7d325_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_7c1157b8-1aee-4a0c-b078-a166452dee08" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_d6273500-010d-498f-a179-a6cea4f7d325" xlink:to="loc_us-gaap_EquityComponentDomain_7c1157b8-1aee-4a0c-b078-a166452dee08" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedTranslationAdjustmentMember_edcf7645-d98b-4543-9fe6-c1bb3745252e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccumulatedTranslationAdjustmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_7c1157b8-1aee-4a0c-b078-a166452dee08" xlink:to="loc_us-gaap_AccumulatedTranslationAdjustmentMember_edcf7645-d98b-4543-9fe6-c1bb3745252e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember_79d89668-0983-4c7a-9e70-8f8dc7709d04" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_7c1157b8-1aee-4a0c-b078-a166452dee08" xlink:to="loc_us-gaap_AccumulatedDefinedBenefitPlansAdjustmentMember_79d89668-0983-4c7a-9e70-8f8dc7709d04" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossBeforeTax1_47f828eb-9128-463a-b8a3-f677afff3c77" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossBeforeTax1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_67e5bd9b-e340-4f4d-a399-881bd611ee24" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossBeforeTax1_47f828eb-9128-463a-b8a3-f677afff3c77" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossBeforeTax_d743933c-9c5f-4137-898d-e2cff46d8f65" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherComprehensiveIncomeLossBeforeTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_67e5bd9b-e340-4f4d-a399-881bd611ee24" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossBeforeTax_d743933c-9c5f-4137-898d-e2cff46d8f65" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossBeforeTax1_40aadcaa-6fc1-4c3d-951b-94264d61d8d7" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossBeforeTax1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossTaxAbstract_daf5624f-5539-41f7-9ffc-23f64f240640" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherComprehensiveIncomeLossTaxAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_67e5bd9b-e340-4f4d-a399-881bd611ee24" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossTaxAbstract_daf5624f-5539-41f7-9ffc-23f64f240640" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_AccumulatedOtherComprehensiveIncomeLossTax_72bfcd92-b1ae-4840-97e0-42accedb2ac2" xlink:href="rock-20231231.xsd#rock_AccumulatedOtherComprehensiveIncomeLossTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossTaxAbstract_daf5624f-5539-41f7-9ffc-23f64f240640" xlink:to="loc_rock_AccumulatedOtherComprehensiveIncomeLossTax_72bfcd92-b1ae-4840-97e0-42accedb2ac2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossTax_4894a0c3-d171-4129-af7d-028ec5b6f6a5" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherComprehensiveIncomeLossTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossTaxAbstract_daf5624f-5539-41f7-9ffc-23f64f240640" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossTax_4894a0c3-d171-4129-af7d-028ec5b6f6a5" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_AccumulatedOtherComprehensiveIncomeLossTax_9fcfdbfc-3653-45ae-b0d1-248b651d57ea" xlink:href="rock-20231231.xsd#rock_AccumulatedOtherComprehensiveIncomeLossTax"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_c3eaf7be-69b9-4626-b688-0bec7187c54a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AOCIAttributableToParentNetOfTaxRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_67e5bd9b-e340-4f4d-a399-881bd611ee24" xlink:to="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_c3eaf7be-69b9-4626-b688-0bec7187c54a" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_b8ca1beb-05e9-46d8-a12d-e2568e7a6813" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_c3eaf7be-69b9-4626-b688-0bec7187c54a" xlink:to="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_b8ca1beb-05e9-46d8-a12d-e2568e7a6813" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansNetOfTax_2af0b39b-6d88-4e83-867b-12796d64802b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_c3eaf7be-69b9-4626-b688-0bec7187c54a" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansNetOfTax_2af0b39b-6d88-4e83-867b-12796d64802b" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_83d9c1ff-09f5-4fc6-9601-b04d4b7d98f0" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OtherComprehensiveIncomeLossNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AOCIAttributableToParentNetOfTaxRollForward_c3eaf7be-69b9-4626-b688-0bec7187c54a" xlink:to="loc_us-gaap_OtherComprehensiveIncomeLossNetOfTax_83d9c1ff-09f5-4fc6-9601-b04d4b7d98f0" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax_25f00a8d-6811-498d-bb23-ef728da22260" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccumulatedOtherComprehensiveIncomeLossNetOfTax"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.gibraltar1.com/role/EquityBasedCompensationNarrativeDetails" xlink:type="simple" xlink:href="rock-20231231.xsd#EquityBasedCompensationNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.gibraltar1.com/role/EquityBasedCompensationNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_34b30513-e377-4ff6-8386-83fc291a173a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_61ba9afb-c7bc-4d34-b8ee-90f4bfe94b7a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_34b30513-e377-4ff6-8386-83fc291a173a" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_61ba9afb-c7bc-4d34-b8ee-90f4bfe94b7a" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationAxis_6a04b268-b562-4bfe-9571-3ee54b758fc8" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BalanceSheetLocationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_61ba9afb-c7bc-4d34-b8ee-90f4bfe94b7a" xlink:to="loc_us-gaap_BalanceSheetLocationAxis_6a04b268-b562-4bfe-9571-3ee54b758fc8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_6a04b268-b562-4bfe-9571-3ee54b758fc8_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_6a04b268-b562-4bfe-9571-3ee54b758fc8" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_6a04b268-b562-4bfe-9571-3ee54b758fc8_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain_b7412f30-a464-4662-a7e1-7b3743c38c77" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_BalanceSheetLocationAxis_6a04b268-b562-4bfe-9571-3ee54b758fc8" xlink:to="loc_us-gaap_BalanceSheetLocationDomain_b7412f30-a464-4662-a7e1-7b3743c38c77" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_AccruedExpensesCurrentMember_50aa5945-9878-4f2e-8dbf-017a136f497d" xlink:href="rock-20231231.xsd#rock_AccruedExpensesCurrentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_b7412f30-a464-4662-a7e1-7b3743c38c77" xlink:to="loc_rock_AccruedExpensesCurrentMember_50aa5945-9878-4f2e-8dbf-017a136f497d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_NonCurrentLiabilitiesMember_0dbe9184-a760-4eb6-9bde-face79def6c6" xlink:href="rock-20231231.xsd#rock_NonCurrentLiabilitiesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_BalanceSheetLocationDomain_b7412f30-a464-4662-a7e1-7b3743c38c77" xlink:to="loc_rock_NonCurrentLiabilitiesMember_0dbe9184-a760-4eb6-9bde-face79def6c6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameAxis_dad16e6e-84bc-45e9-96f8-00bb16fb5b55" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PlanNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_61ba9afb-c7bc-4d34-b8ee-90f4bfe94b7a" xlink:to="loc_us-gaap_PlanNameAxis_dad16e6e-84bc-45e9-96f8-00bb16fb5b55" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameDomain_dad16e6e-84bc-45e9-96f8-00bb16fb5b55_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PlanNameAxis_dad16e6e-84bc-45e9-96f8-00bb16fb5b55" xlink:to="loc_us-gaap_PlanNameDomain_dad16e6e-84bc-45e9-96f8-00bb16fb5b55_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameDomain_19be69e4-0dd6-4bf9-b6a2-773775cd78df" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PlanNameAxis_dad16e6e-84bc-45e9-96f8-00bb16fb5b55" xlink:to="loc_us-gaap_PlanNameDomain_19be69e4-0dd6-4bf9-b6a2-773775cd78df" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_A2018PlanMember_1844fa4f-7a0c-4288-9187-19bc44055b15" xlink:href="rock-20231231.xsd#rock_A2018PlanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_19be69e4-0dd6-4bf9-b6a2-773775cd78df" xlink:to="loc_rock_A2018PlanMember_1844fa4f-7a0c-4288-9187-19bc44055b15" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_TwoThousandEighteenEquityIncentivePlanMember_fa5f361c-8913-47a7-be25-4b5c4db4ac1f" xlink:href="rock-20231231.xsd#rock_TwoThousandEighteenEquityIncentivePlanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_19be69e4-0dd6-4bf9-b6a2-773775cd78df" xlink:to="loc_rock_TwoThousandEighteenEquityIncentivePlanMember_fa5f361c-8913-47a7-be25-4b5c4db4ac1f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_NonEmployeeDirectorsPlanMember_5cb53564-3c29-484a-aebe-2586a26c36bd" xlink:href="rock-20231231.xsd#rock_NonEmployeeDirectorsPlanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_19be69e4-0dd6-4bf9-b6a2-773775cd78df" xlink:to="loc_rock_NonEmployeeDirectorsPlanMember_5cb53564-3c29-484a-aebe-2586a26c36bd" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_ManagementStockPurchasePlanMember_c655b661-0038-44c1-8986-25c9c1f7392a" xlink:href="rock-20231231.xsd#rock_ManagementStockPurchasePlanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_19be69e4-0dd6-4bf9-b6a2-773775cd78df" xlink:to="loc_rock_ManagementStockPurchasePlanMember_c655b661-0038-44c1-8986-25c9c1f7392a" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_Amended2018PlanMember_5d8252dd-2b15-446f-aefa-657b73499309" xlink:href="rock-20231231.xsd#rock_Amended2018PlanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_19be69e4-0dd6-4bf9-b6a2-773775cd78df" xlink:to="loc_rock_Amended2018PlanMember_5d8252dd-2b15-446f-aefa-657b73499309" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_A2015PlanMember_ed4a3d3c-9d14-4cd1-9174-c75db008c60c" xlink:href="rock-20231231.xsd#rock_A2015PlanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_19be69e4-0dd6-4bf9-b6a2-773775cd78df" xlink:to="loc_rock_A2015PlanMember_ed4a3d3c-9d14-4cd1-9174-c75db008c60c" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_6de0c604-7699-48ae-b121-afca3ac73469" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_61ba9afb-c7bc-4d34-b8ee-90f4bfe94b7a" xlink:to="loc_us-gaap_AwardTypeAxis_6de0c604-7699-48ae-b121-afca3ac73469" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_6de0c604-7699-48ae-b121-afca3ac73469_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_6de0c604-7699-48ae-b121-afca3ac73469" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_6de0c604-7699-48ae-b121-afca3ac73469_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_d335f699-6b79-42ea-a222-4dae0034b30c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_6de0c604-7699-48ae-b121-afca3ac73469" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_d335f699-6b79-42ea-a222-4dae0034b30c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember_b09a4925-96cd-442a-8fba-fb2a7a2baabb" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommonStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_d335f699-6b79-42ea-a222-4dae0034b30c" xlink:to="loc_us-gaap_CommonStockMember_b09a4925-96cd-442a-8fba-fb2a7a2baabb" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PerformanceSharesMember_463a5d1e-1e5a-4cb0-aa75-d21376460587" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PerformanceSharesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_d335f699-6b79-42ea-a222-4dae0034b30c" xlink:to="loc_us-gaap_PerformanceSharesMember_463a5d1e-1e5a-4cb0-aa75-d21376460587" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockUnitsRSUMember_fb17a4e3-55c1-4f11-b52c-ff442f2821e3" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RestrictedStockUnitsRSUMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_d335f699-6b79-42ea-a222-4dae0034b30c" xlink:to="loc_us-gaap_RestrictedStockUnitsRSUMember_fb17a4e3-55c1-4f11-b52c-ff442f2821e3" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_36f884ad-6412-472e-a9cb-3e226e90c117" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_61ba9afb-c7bc-4d34-b8ee-90f4bfe94b7a" xlink:to="loc_srt_RangeAxis_36f884ad-6412-472e-a9cb-3e226e90c117" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_36f884ad-6412-472e-a9cb-3e226e90c117_default" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_36f884ad-6412-472e-a9cb-3e226e90c117" xlink:to="loc_srt_RangeMember_36f884ad-6412-472e-a9cb-3e226e90c117_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_dfae184e-5ab7-4e6d-af0b-28c02c261b34" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_36f884ad-6412-472e-a9cb-3e226e90c117" xlink:to="loc_srt_RangeMember_dfae184e-5ab7-4e6d-af0b-28c02c261b34" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_fa511489-4fbd-4567-ad18-af63082f3304" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_dfae184e-5ab7-4e6d-af0b-28c02c261b34" xlink:to="loc_srt_MaximumMember_fa511489-4fbd-4567-ad18-af63082f3304" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_22ac1160-f07c-42f0-9c8f-37b5c5ef906d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_61ba9afb-c7bc-4d34-b8ee-90f4bfe94b7a" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_22ac1160-f07c-42f0-9c8f-37b5c5ef906d" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_22ac1160-f07c-42f0-9c8f-37b5c5ef906d_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_22ac1160-f07c-42f0-9c8f-37b5c5ef906d" xlink:to="loc_us-gaap_EquityComponentDomain_22ac1160-f07c-42f0-9c8f-37b5c5ef906d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_4a47f492-9607-4d82-ae6d-ae87873c31c3" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_22ac1160-f07c-42f0-9c8f-37b5c5ef906d" xlink:to="loc_us-gaap_EquityComponentDomain_4a47f492-9607-4d82-ae6d-ae87873c31c3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_ManagementStockPurchasePlanMember_8928e56c-9bca-486e-ba0d-432e357e26dc" xlink:href="rock-20231231.xsd#rock_ManagementStockPurchasePlanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_4a47f492-9607-4d82-ae6d-ae87873c31c3" xlink:to="loc_rock_ManagementStockPurchasePlanMember_8928e56c-9bca-486e-ba0d-432e357e26dc" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_bccc3631-c708-4023-9cf4-fc1db2e91fbd" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_34b30513-e377-4ff6-8386-83fc291a173a" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardAwardVestingPeriod1_bccc3631-c708-4023-9cf4-fc1db2e91fbd" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized_852bbb98-9b60-4ffe-8196-b8ec75fca5f3" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_34b30513-e377-4ff6-8386-83fc291a173a" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized_852bbb98-9b60-4ffe-8196-b8ec75fca5f3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant_738eee53-0cb9-45bb-adb4-bc11fbfa2363" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_34b30513-e377-4ff6-8386-83fc291a173a" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAvailableForGrant_738eee53-0cb9-45bb-adb4-bc11fbfa2363" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross_9325e667-a33b-4a12-8f8e-c3c87df0829b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_34b30513-e377-4ff6-8386-83fc291a173a" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross_9325e667-a33b-4a12-8f8e-c3c87df0829b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_MarketPriceOfCommonStockPerShare_e6c6e8e8-a6fe-4759-aff6-a1cb46e69cf4" xlink:href="rock-20231231.xsd#rock_MarketPriceOfCommonStockPerShare"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_34b30513-e377-4ff6-8386-83fc291a173a" xlink:to="loc_rock_MarketPriceOfCommonStockPerShare_e6c6e8e8-a6fe-4759-aff6-a1cb46e69cf4" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_d76e3e63-68d2-43eb-a356-1d799ae52e91" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_34b30513-e377-4ff6-8386-83fc291a173a" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_d76e3e63-68d2-43eb-a356-1d799ae52e91" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_SharebasedCompensationArrangementbySharebasedPaymentAwardAwardPerformancePeriod_9f67eb47-a7cf-4b05-a989-551263a940ce" xlink:href="rock-20231231.xsd#rock_SharebasedCompensationArrangementbySharebasedPaymentAwardAwardPerformancePeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_34b30513-e377-4ff6-8386-83fc291a173a" xlink:to="loc_rock_SharebasedCompensationArrangementbySharebasedPaymentAwardAwardPerformancePeriod_9f67eb47-a7cf-4b05-a989-551263a940ce" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_4fbf7124-b4d7-474c-b170-ec9aa9c7eae6" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_34b30513-e377-4ff6-8386-83fc291a173a" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_4fbf7124-b4d7-474c-b170-ec9aa9c7eae6" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_9af237da-8e56-45f1-9ac2-d53f521689d6" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_34b30513-e377-4ff6-8386-83fc291a173a" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_9af237da-8e56-45f1-9ac2-d53f521689d6" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized_18e8f49d-cde0-4e0b-98bb-c3e1fa01c855" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_34b30513-e377-4ff6-8386-83fc291a173a" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized_18e8f49d-cde0-4e0b-98bb-c3e1fa01c855" xlink:type="arc" order="9"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_2c53ce54-bb7a-448e-94f1-54d803b2451d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_34b30513-e377-4ff6-8386-83fc291a173a" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognizedPeriodForRecognition1_2c53ce54-bb7a-448e-94f1-54d803b2451d" xlink:type="arc" order="10"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_AccruedEquityBasedCompensation_f099bf74-77dc-47e0-a3a0-8c3ac13ee0de" xlink:href="rock-20231231.xsd#rock_AccruedEquityBasedCompensation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_34b30513-e377-4ff6-8386-83fc291a173a" xlink:to="loc_rock_AccruedEquityBasedCompensation_f099bf74-77dc-47e0-a3a0-8c3ac13ee0de" xlink:type="arc" order="11"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_SharebasedCompensationArrangementBySharebasedPaymentAwardAverageCompanyStockPriceMeasurementPeriod_1ac647c9-2998-4489-95a1-1065bd1e6b35" xlink:href="rock-20231231.xsd#rock_SharebasedCompensationArrangementBySharebasedPaymentAwardAverageCompanyStockPriceMeasurementPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_34b30513-e377-4ff6-8386-83fc291a173a" xlink:to="loc_rock_SharebasedCompensationArrangementBySharebasedPaymentAwardAverageCompanyStockPriceMeasurementPeriod_1ac647c9-2998-4489-95a1-1065bd1e6b35" xlink:type="arc" order="12"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantOutstandingNumber_e09b39e6-619f-4764-9b4b-c5ff8d385142" xlink:href="rock-20231231.xsd#rock_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantOutstandingNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_34b30513-e377-4ff6-8386-83fc291a173a" xlink:to="loc_rock_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantOutstandingNumber_e09b39e6-619f-4764-9b4b-c5ff8d385142" xlink:type="arc" order="13"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.gibraltar1.com/role/EquityBasedCompensationSummaryofCompensationExpenseConnectionwithAwardsDetails" xlink:type="simple" xlink:href="rock-20231231.xsd#EquityBasedCompensationSummaryofCompensationExpenseConnectionwithAwardsDetails"/>
  <link:definitionLink xlink:role="http://www.gibraltar1.com/role/EquityBasedCompensationSummaryofCompensationExpenseConnectionwithAwardsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_0338d1d4-a82d-4027-bafe-209b351d5308" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_d9c006b4-04c6-4687-80b9-8b4144ad2360" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_0338d1d4-a82d-4027-bafe-209b351d5308" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_d9c006b4-04c6-4687-80b9-8b4144ad2360" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameAxis_f788a621-f771-4baa-a1e4-7b7b4a42888d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PlanNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_d9c006b4-04c6-4687-80b9-8b4144ad2360" xlink:to="loc_us-gaap_PlanNameAxis_f788a621-f771-4baa-a1e4-7b7b4a42888d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameDomain_f788a621-f771-4baa-a1e4-7b7b4a42888d_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PlanNameAxis_f788a621-f771-4baa-a1e4-7b7b4a42888d" xlink:to="loc_us-gaap_PlanNameDomain_f788a621-f771-4baa-a1e4-7b7b4a42888d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameDomain_30ec5603-1f73-4ca6-8722-8f7bc614d362" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PlanNameAxis_f788a621-f771-4baa-a1e4-7b7b4a42888d" xlink:to="loc_us-gaap_PlanNameDomain_30ec5603-1f73-4ca6-8722-8f7bc614d362" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_A2015PlanMember_8687cd4c-13e8-4045-b8ca-78dde48bfec9" xlink:href="rock-20231231.xsd#rock_A2015PlanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_30ec5603-1f73-4ca6-8722-8f7bc614d362" xlink:to="loc_rock_A2015PlanMember_8687cd4c-13e8-4045-b8ca-78dde48bfec9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_A2018PlanMember_acaf5d6a-bed4-4091-91ba-7bb8555df279" xlink:href="rock-20231231.xsd#rock_A2018PlanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_30ec5603-1f73-4ca6-8722-8f7bc614d362" xlink:to="loc_rock_A2018PlanMember_acaf5d6a-bed4-4091-91ba-7bb8555df279" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensation_0b520ffe-bbb1-4e92-af97-a96fdb518904" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensation"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_0338d1d4-a82d-4027-bafe-209b351d5308" xlink:to="loc_us-gaap_ShareBasedCompensation_0b520ffe-bbb1-4e92-af97-a96fdb518904" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense_fa0fd149-b6bf-46f1-8534-b16a954be8b8" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_0338d1d4-a82d-4027-bafe-209b351d5308" xlink:to="loc_us-gaap_EmployeeServiceShareBasedCompensationTaxBenefitFromCompensationExpense_fa0fd149-b6bf-46f1-8534-b16a954be8b8" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.gibraltar1.com/role/EquityBasedCompensationScheduleofNumberofAwardsandWeightedAverageGrantDateFairValueDetails" xlink:type="simple" xlink:href="rock-20231231.xsd#EquityBasedCompensationScheduleofNumberofAwardsandWeightedAverageGrantDateFairValueDetails"/>
  <link:definitionLink xlink:role="http://www.gibraltar1.com/role/EquityBasedCompensationScheduleofNumberofAwardsandWeightedAverageGrantDateFairValueDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_76b779b9-3ed5-400d-a18a-0ed48d58fae0" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_2fe13363-ead8-4215-a215-05f9a65ccdc3" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_76b779b9-3ed5-400d-a18a-0ed48d58fae0" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_2fe13363-ead8-4215-a215-05f9a65ccdc3" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardDateAxis_73f2cf7d-89d2-456a-8665-652f874a00c7" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AwardDateAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_2fe13363-ead8-4215-a215-05f9a65ccdc3" xlink:to="loc_us-gaap_AwardDateAxis_73f2cf7d-89d2-456a-8665-652f874a00c7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardDateDomain_73f2cf7d-89d2-456a-8665-652f874a00c7_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AwardDateDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardDateAxis_73f2cf7d-89d2-456a-8665-652f874a00c7" xlink:to="loc_us-gaap_AwardDateDomain_73f2cf7d-89d2-456a-8665-652f874a00c7_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardDateDomain_10054d26-1e29-4641-84b5-9d159491a8dd" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AwardDateDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardDateAxis_73f2cf7d-89d2-456a-8665-652f874a00c7" xlink:to="loc_us-gaap_AwardDateDomain_10054d26-1e29-4641-84b5-9d159491a8dd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_A2019Member_22be4690-d4a6-4c46-9f00-f57ae5bb86f9" xlink:href="rock-20231231.xsd#rock_A2019Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AwardDateDomain_10054d26-1e29-4641-84b5-9d159491a8dd" xlink:to="loc_rock_A2019Member_22be4690-d4a6-4c46-9f00-f57ae5bb86f9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_A2018Member_61f2bf1f-1528-4ce9-a5a4-1a6d2e0e9e6c" xlink:href="rock-20231231.xsd#rock_A2018Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AwardDateDomain_10054d26-1e29-4641-84b5-9d159491a8dd" xlink:to="loc_rock_A2018Member_61f2bf1f-1528-4ce9-a5a4-1a6d2e0e9e6c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_A2017Member_d9d0b492-5dae-4b8b-8178-01b7670a0a6c" xlink:href="rock-20231231.xsd#rock_A2017Member"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AwardDateDomain_10054d26-1e29-4641-84b5-9d159491a8dd" xlink:to="loc_rock_A2017Member_d9d0b492-5dae-4b8b-8178-01b7670a0a6c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_b12a073d-dd78-49a3-ba2b-0002ca1d6a54" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_2fe13363-ead8-4215-a215-05f9a65ccdc3" xlink:to="loc_us-gaap_AwardTypeAxis_b12a073d-dd78-49a3-ba2b-0002ca1d6a54" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_b12a073d-dd78-49a3-ba2b-0002ca1d6a54_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_b12a073d-dd78-49a3-ba2b-0002ca1d6a54" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_b12a073d-dd78-49a3-ba2b-0002ca1d6a54_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_691d4cce-a5b5-4f0a-9cb3-a079fef6e8b6" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_b12a073d-dd78-49a3-ba2b-0002ca1d6a54" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_691d4cce-a5b5-4f0a-9cb3-a079fef6e8b6" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_DeferredStockUnitsMember_febdd222-8d84-4b19-8c3d-8c6cf17f58ed" xlink:href="rock-20231231.xsd#rock_DeferredStockUnitsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_691d4cce-a5b5-4f0a-9cb3-a079fef6e8b6" xlink:to="loc_rock_DeferredStockUnitsMember_febdd222-8d84-4b19-8c3d-8c6cf17f58ed" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockMember_91b40ff9-fa67-4b8d-9488-94825e6bfbee" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RestrictedStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_691d4cce-a5b5-4f0a-9cb3-a079fef6e8b6" xlink:to="loc_us-gaap_RestrictedStockMember_91b40ff9-fa67-4b8d-9488-94825e6bfbee" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockUnitsRSUMember_ee7d59a5-e998-477c-b310-db797e088561" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RestrictedStockUnitsRSUMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_691d4cce-a5b5-4f0a-9cb3-a079fef6e8b6" xlink:to="loc_us-gaap_RestrictedStockUnitsRSUMember_ee7d59a5-e998-477c-b310-db797e088561" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PerformanceSharesMember_25326602-f21e-4ef9-8148-f046b4bc30cc" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PerformanceSharesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_691d4cce-a5b5-4f0a-9cb3-a079fef6e8b6" xlink:to="loc_us-gaap_PerformanceSharesMember_25326602-f21e-4ef9-8148-f046b4bc30cc" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_33d67177-f694-4866-9bee-5dc3f90bc39c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_76b779b9-3ed5-400d-a18a-0ed48d58fae0" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_33d67177-f694-4866-9bee-5dc3f90bc39c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_df985bc4-35a1-4216-8024-0d5a50beb689" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_76b779b9-3ed5-400d-a18a-0ed48d58fae0" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_df985bc4-35a1-4216-8024-0d5a50beb689" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.gibraltar1.com/role/EquityBasedCompensationSummaryofRangesofOutstandingandExercisableOptionsDetails" xlink:type="simple" xlink:href="rock-20231231.xsd#EquityBasedCompensationSummaryofRangesofOutstandingandExercisableOptionsDetails"/>
  <link:definitionLink xlink:role="http://www.gibraltar1.com/role/EquityBasedCompensationSummaryofRangesofOutstandingandExercisableOptionsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems_4840cdce-50d6-47f3-8caf-29bed5391e35" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeTable_8b261ba5-f050-4d7e-90de-251c56a909a5" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems_4840cdce-50d6-47f3-8caf-29bed5391e35" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeTable_8b261ba5-f050-4d7e-90de-251c56a909a5" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis_2e4a01ca-18bd-4ca7-9f6d-18d942d558dd" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeTable_8b261ba5-f050-4d7e-90de-251c56a909a5" xlink:to="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis_2e4a01ca-18bd-4ca7-9f6d-18d942d558dd" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_2e4a01ca-18bd-4ca7-9f6d-18d942d558dd_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis_2e4a01ca-18bd-4ca7-9f6d-18d942d558dd" xlink:to="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_2e4a01ca-18bd-4ca7-9f6d-18d942d558dd_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_11182170-ffd3-4e1b-bd73-3242abb24641" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeAxis_2e4a01ca-18bd-4ca7-9f6d-18d942d558dd" xlink:to="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_11182170-ffd3-4e1b-bd73-3242abb24641" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_ExercisePriceRangeOneMember_be2f47e5-52bb-485e-9b0c-799559a2dd43" xlink:href="rock-20231231.xsd#rock_ExercisePriceRangeOneMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeDomain_11182170-ffd3-4e1b-bd73-3242abb24641" xlink:to="loc_rock_ExercisePriceRangeOneMember_be2f47e5-52bb-485e-9b0c-799559a2dd43" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLowerRangeLimit_aab6999b-a7e7-4ed4-8129-0a4e0c0059d4" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLowerRangeLimit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems_4840cdce-50d6-47f3-8caf-29bed5391e35" xlink:to="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLowerRangeLimit_aab6999b-a7e7-4ed4-8129-0a4e0c0059d4" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber_c3d92711-0f68-483b-beb8-562843e39db0" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems_4840cdce-50d6-47f3-8caf-29bed5391e35" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber_c3d92711-0f68-483b-beb8-562843e39db0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2_b12b4477-b3b3-48c3-92f1-a8769fe6e93e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems_4840cdce-50d6-47f3-8caf-29bed5391e35" xlink:to="loc_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsOutstandingWeightedAverageRemainingContractualTerm2_b12b4477-b3b3-48c3-92f1-a8769fe6e93e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice_88575d00-242e-40ce-8d07-3c560c3c6a0d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems_4840cdce-50d6-47f3-8caf-29bed5391e35" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice_88575d00-242e-40ce-8d07-3c560c3c6a0d" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber_b390a5a9-b1be-4831-849c-3c30762797ae" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems_4840cdce-50d6-47f3-8caf-29bed5391e35" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableNumber_b390a5a9-b1be-4831-849c-3c30762797ae" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice_b88e93fe-f397-4c00-a07c-a37c5ad4ebbb" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceRangeLineItems_4840cdce-50d6-47f3-8caf-29bed5391e35" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice_b88e93fe-f397-4c00-a07c-a37c5ad4ebbb" xlink:type="arc" order="5"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.gibraltar1.com/role/EquityBasedCompensationSummaryofInformationaboutRestrictedStockUnitsandWeightedAverageGrantDateFairValueDetails" xlink:type="simple" xlink:href="rock-20231231.xsd#EquityBasedCompensationSummaryofInformationaboutRestrictedStockUnitsandWeightedAverageGrantDateFairValueDetails"/>
  <link:definitionLink xlink:role="http://www.gibraltar1.com/role/EquityBasedCompensationSummaryofInformationaboutRestrictedStockUnitsandWeightedAverageGrantDateFairValueDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_ee10c90e-495b-40d6-8876-3860e65270a1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_616d6bc3-1180-4f69-bdd3-438e20418f9f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_ee10c90e-495b-40d6-8876-3860e65270a1" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_616d6bc3-1180-4f69-bdd3-438e20418f9f" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameAxis_5c311f9f-9603-4e52-8e7b-993de626095d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PlanNameAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_616d6bc3-1180-4f69-bdd3-438e20418f9f" xlink:to="loc_us-gaap_PlanNameAxis_5c311f9f-9603-4e52-8e7b-993de626095d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameDomain_5c311f9f-9603-4e52-8e7b-993de626095d_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_PlanNameAxis_5c311f9f-9603-4e52-8e7b-993de626095d" xlink:to="loc_us-gaap_PlanNameDomain_5c311f9f-9603-4e52-8e7b-993de626095d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameDomain_72b0afa2-cce8-4abb-b4c7-2dfdc13aff9a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_PlanNameAxis_5c311f9f-9603-4e52-8e7b-993de626095d" xlink:to="loc_us-gaap_PlanNameDomain_72b0afa2-cce8-4abb-b4c7-2dfdc13aff9a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_TwoThousandEighteenEquityIncentivePlanMember_7e0d5af2-8247-448a-ad8f-f92f1e9a9dc3" xlink:href="rock-20231231.xsd#rock_TwoThousandEighteenEquityIncentivePlanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_72b0afa2-cce8-4abb-b4c7-2dfdc13aff9a" xlink:to="loc_rock_TwoThousandEighteenEquityIncentivePlanMember_7e0d5af2-8247-448a-ad8f-f92f1e9a9dc3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_A2018PlanMember_100492c3-d17f-4834-9cc2-2c99cd88f974" xlink:href="rock-20231231.xsd#rock_A2018PlanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_PlanNameDomain_72b0afa2-cce8-4abb-b4c7-2dfdc13aff9a" xlink:to="loc_rock_A2018PlanMember_100492c3-d17f-4834-9cc2-2c99cd88f974" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputTypeAxis_75404079-b743-4d88-ae94-8bc257fff3e2" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_MeasurementInputTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_616d6bc3-1180-4f69-bdd3-438e20418f9f" xlink:to="loc_us-gaap_MeasurementInputTypeAxis_75404079-b743-4d88-ae94-8bc257fff3e2" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputTypeDomain_75404079-b743-4d88-ae94-8bc257fff3e2_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_MeasurementInputTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_MeasurementInputTypeAxis_75404079-b743-4d88-ae94-8bc257fff3e2" xlink:to="loc_us-gaap_MeasurementInputTypeDomain_75404079-b743-4d88-ae94-8bc257fff3e2_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MeasurementInputTypeDomain_443a2df8-62a0-488f-ac0d-846985923e18" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_MeasurementInputTypeDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_MeasurementInputTypeAxis_75404079-b743-4d88-ae94-8bc257fff3e2" xlink:to="loc_us-gaap_MeasurementInputTypeDomain_443a2df8-62a0-488f-ac0d-846985923e18" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_SharebasedCompensationMeasurementReturnOnInvestedCapitalMember_fdefaa21-a8c8-46d9-b6fd-ddc549f2ba51" xlink:href="rock-20231231.xsd#rock_SharebasedCompensationMeasurementReturnOnInvestedCapitalMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MeasurementInputTypeDomain_443a2df8-62a0-488f-ac0d-846985923e18" xlink:to="loc_rock_SharebasedCompensationMeasurementReturnOnInvestedCapitalMember_fdefaa21-a8c8-46d9-b6fd-ddc549f2ba51" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_0c8944ca-c7a7-4ade-bc74-287367ddb10f" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_616d6bc3-1180-4f69-bdd3-438e20418f9f" xlink:to="loc_srt_RangeAxis_0c8944ca-c7a7-4ade-bc74-287367ddb10f" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_0c8944ca-c7a7-4ade-bc74-287367ddb10f_default" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_0c8944ca-c7a7-4ade-bc74-287367ddb10f" xlink:to="loc_srt_RangeMember_0c8944ca-c7a7-4ade-bc74-287367ddb10f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_34b5bbb9-8fd1-45ed-81d2-1beef1ce4b49" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_0c8944ca-c7a7-4ade-bc74-287367ddb10f" xlink:to="loc_srt_RangeMember_34b5bbb9-8fd1-45ed-81d2-1beef1ce4b49" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_51781483-5acd-4217-98ca-8fe28d7264ee" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_34b5bbb9-8fd1-45ed-81d2-1beef1ce4b49" xlink:to="loc_srt_MinimumMember_51781483-5acd-4217-98ca-8fe28d7264ee" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_04952244-f488-4eab-9ffd-631de0cac5b1" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_34b5bbb9-8fd1-45ed-81d2-1beef1ce4b49" xlink:to="loc_srt_MaximumMember_04952244-f488-4eab-9ffd-631de0cac5b1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_5e5d09d5-94f1-496f-a256-e8a678bd1f80" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_616d6bc3-1180-4f69-bdd3-438e20418f9f" xlink:to="loc_us-gaap_AwardTypeAxis_5e5d09d5-94f1-496f-a256-e8a678bd1f80" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_5e5d09d5-94f1-496f-a256-e8a678bd1f80_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_5e5d09d5-94f1-496f-a256-e8a678bd1f80" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_5e5d09d5-94f1-496f-a256-e8a678bd1f80_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_9743aecd-7747-4396-b86b-65780217468b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_5e5d09d5-94f1-496f-a256-e8a678bd1f80" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_9743aecd-7747-4396-b86b-65780217468b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockUnitsRSUMember_f59f04f0-3aa6-424d-8173-ed4fd1c77658" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RestrictedStockUnitsRSUMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_9743aecd-7747-4396-b86b-65780217468b" xlink:to="loc_us-gaap_RestrictedStockUnitsRSUMember_f59f04f0-3aa6-424d-8173-ed4fd1c77658" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockMember_c198d837-9933-45d1-8b4a-6943ca498c74" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RestrictedStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_9743aecd-7747-4396-b86b-65780217468b" xlink:to="loc_us-gaap_RestrictedStockMember_c198d837-9933-45d1-8b4a-6943ca498c74" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PerformanceSharesMember_aea28bd7-89f6-4b7a-88ed-921d9551c381" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PerformanceSharesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_9743aecd-7747-4396-b86b-65780217468b" xlink:to="loc_us-gaap_PerformanceSharesMember_aea28bd7-89f6-4b7a-88ed-921d9551c381" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_DeferredStockUnitsMember_718f0731-9ee8-4d14-99b0-02cdbf9cf443" xlink:href="rock-20231231.xsd#rock_DeferredStockUnitsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_9743aecd-7747-4396-b86b-65780217468b" xlink:to="loc_rock_DeferredStockUnitsMember_718f0731-9ee8-4d14-99b0-02cdbf9cf443" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_35ed674b-fbfe-4408-953e-5d3cd885d902" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_ee10c90e-495b-40d6-8876-3860e65270a1" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_35ed674b-fbfe-4408-953e-5d3cd885d902" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_1874e645-8956-4e26-a5b4-64d03069f0ed" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_35ed674b-fbfe-4408-953e-5d3cd885d902" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_1874e645-8956-4e26-a5b4-64d03069f0ed" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_32a656bf-577b-4ab7-aaa8-89a6e83ac8de" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_35ed674b-fbfe-4408-953e-5d3cd885d902" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_32a656bf-577b-4ab7-aaa8-89a6e83ac8de" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsAdjustmentsInPeriod_03a6aeac-4fce-48ef-b9c5-d23aceb8317b" xlink:href="rock-20231231.xsd#rock_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsAdjustmentsInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_35ed674b-fbfe-4408-953e-5d3cd885d902" xlink:to="loc_rock_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsAdjustmentsInPeriod_03a6aeac-4fce-48ef-b9c5-d23aceb8317b" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_b7fe45d0-f3b7-4d8e-9abb-970fcc23d323" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_35ed674b-fbfe-4408-953e-5d3cd885d902" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_b7fe45d0-f3b7-4d8e-9abb-970fcc23d323" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_4490d994-f5a0-4643-a0d5-55073ef3470f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedRollForward_35ed674b-fbfe-4408-953e-5d3cd885d902" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeitedInPeriod_4490d994-f5a0-4643-a0d5-55073ef3470f" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber_4b7302d9-6818-49cb-9cf0-05b76e0da138" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedNumber"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_a5b96902-8181-4edf-b6d7-176d9c371948" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_ee10c90e-495b-40d6-8876-3860e65270a1" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_a5b96902-8181-4edf-b6d7-176d9c371948" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_92eb82ec-e914-41be-bf31-93d8591fa1e3" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_a5b96902-8181-4edf-b6d7-176d9c371948" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_92eb82ec-e914-41be-bf31-93d8591fa1e3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_69b3d602-d9b3-4969-8b72-aeee772d4266" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_a5b96902-8181-4edf-b6d7-176d9c371948" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_69b3d602-d9b3-4969-8b72-aeee772d4266" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsAdjustmentsInPeriodWeightedAverageGrantDateFairValue_83f18c7e-6070-440b-a8ba-92458962013e" xlink:href="rock-20231231.xsd#rock_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsAdjustmentsInPeriodWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_a5b96902-8181-4edf-b6d7-176d9c371948" xlink:to="loc_rock_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsAdjustmentsInPeriodWeightedAverageGrantDateFairValue_83f18c7e-6070-440b-a8ba-92458962013e" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_f79d9de8-3f1c-4802-a795-54b0b1fc7873" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_a5b96902-8181-4edf-b6d7-176d9c371948" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_f79d9de8-3f1c-4802-a795-54b0b1fc7873" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_709abbd5-bbb8-4337-abd6-ad58eb3aad4f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValueRollForward_a5b96902-8181-4edf-b6d7-176d9c371948" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsForfeituresWeightedAverageGrantDateFairValue_709abbd5-bbb8-4337-abd6-ad58eb3aad4f" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue_6b843dc9-8070-4a6d-88ac-bf71ce03f443" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsNonvestedWeightedAverageGrantDateFairValue"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_SharebasedCompensationArrangementbySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsBasedOnTargetedThresholdsPercent_b2f98122-2591-4b99-9abe-25f683e44fda" xlink:href="rock-20231231.xsd#rock_SharebasedCompensationArrangementbySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsBasedOnTargetedThresholdsPercent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_ee10c90e-495b-40d6-8876-3860e65270a1" xlink:to="loc_rock_SharebasedCompensationArrangementbySharebasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsBasedOnTargetedThresholdsPercent_b2f98122-2591-4b99-9abe-25f683e44fda" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_SharebasedCompensationArrangementbySharebasedPaymentAwardAwardPerformancePeriod_e3cac280-7382-42aa-976c-a5e8d085c509" xlink:href="rock-20231231.xsd#rock_SharebasedCompensationArrangementbySharebasedPaymentAwardAwardPerformancePeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_ee10c90e-495b-40d6-8876-3860e65270a1" xlink:to="loc_rock_SharebasedCompensationArrangementbySharebasedPaymentAwardAwardPerformancePeriod_e3cac280-7382-42aa-976c-a5e8d085c509" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsAdjustmentsInPeriodPerformanceConditionsNotAchieved_ef81fbdf-3636-41a4-b323-9ec2fb615f87" xlink:href="rock-20231231.xsd#rock_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsAdjustmentsInPeriodPerformanceConditionsNotAchieved"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_ee10c90e-495b-40d6-8876-3860e65270a1" xlink:to="loc_rock_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsAdjustmentsInPeriodPerformanceConditionsNotAchieved_ef81fbdf-3636-41a4-b323-9ec2fb615f87" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsTargetPortionGranted_e1bac505-8a57-4b09-b530-e964b4db6ecb" xlink:href="rock-20231231.xsd#rock_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsTargetPortionGranted"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_ee10c90e-495b-40d6-8876-3860e65270a1" xlink:to="loc_rock_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsTargetPortionGranted_e1bac505-8a57-4b09-b530-e964b4db6ecb" xlink:type="arc" order="5"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.gibraltar1.com/role/EquityBasedCompensationAggregateIntrinsicValueofOptionsExercisedandAggregateFairValueofRestrictedStockUnitsandRestrictedSharesthatVestedDetails" xlink:type="simple" xlink:href="rock-20231231.xsd#EquityBasedCompensationAggregateIntrinsicValueofOptionsExercisedandAggregateFairValueofRestrictedStockUnitsandRestrictedSharesthatVestedDetails"/>
  <link:definitionLink xlink:role="http://www.gibraltar1.com/role/EquityBasedCompensationAggregateIntrinsicValueofOptionsExercisedandAggregateFairValueofRestrictedStockUnitsandRestrictedSharesthatVestedDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_e05cab29-220b-413c-94f0-b71a29d670eb" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeTable_f25d2bd7-8992-418c-b6bd-2df6aee23f6a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_e05cab29-220b-413c-94f0-b71a29d670eb" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeTable_f25d2bd7-8992-418c-b6bd-2df6aee23f6a" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_aca571d6-fe12-4a3d-b8f0-4dc34adcfa1d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationSharesAuthorizedUnderStockOptionPlansByExercisePriceRangeTable_f25d2bd7-8992-418c-b6bd-2df6aee23f6a" xlink:to="loc_us-gaap_AwardTypeAxis_aca571d6-fe12-4a3d-b8f0-4dc34adcfa1d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_aca571d6-fe12-4a3d-b8f0-4dc34adcfa1d_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_aca571d6-fe12-4a3d-b8f0-4dc34adcfa1d" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_aca571d6-fe12-4a3d-b8f0-4dc34adcfa1d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_76c7532c-f595-4005-87b6-31219de4c7da" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_aca571d6-fe12-4a3d-b8f0-4dc34adcfa1d" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_76c7532c-f595-4005-87b6-31219de4c7da" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockUnitsRSUMember_7ab37797-b6d3-4419-a433-5e37b9870ea1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RestrictedStockUnitsRSUMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_76c7532c-f595-4005-87b6-31219de4c7da" xlink:to="loc_us-gaap_RestrictedStockUnitsRSUMember_7ab37797-b6d3-4419-a433-5e37b9870ea1" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockMember_0e646db9-8feb-4a63-8b67-3341a053bb02" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RestrictedStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_76c7532c-f595-4005-87b6-31219de4c7da" xlink:to="loc_us-gaap_RestrictedStockMember_0e646db9-8feb-4a63-8b67-3341a053bb02" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_PerformanceStockUnitsMember_e00586f0-cab0-4bf1-8e29-661f9d2eb33e" xlink:href="rock-20231231.xsd#rock_PerformanceStockUnitsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_76c7532c-f595-4005-87b6-31219de4c7da" xlink:to="loc_rock_PerformanceStockUnitsMember_e00586f0-cab0-4bf1-8e29-661f9d2eb33e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_DeferredStockUnitsMember_a4bc5f8f-a131-4c27-be8b-3ab2baea2113" xlink:href="rock-20231231.xsd#rock_DeferredStockUnitsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_76c7532c-f595-4005-87b6-31219de4c7da" xlink:to="loc_rock_DeferredStockUnitsMember_a4bc5f8f-a131-4c27-be8b-3ab2baea2113" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue_74b063c1-1608-48e5-85ad-99e66973b72e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_e05cab29-220b-413c-94f0-b71a29d670eb" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue_74b063c1-1608-48e5-85ad-99e66973b72e" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue_98358f7b-8a6e-4b60-a3e7-e43976295422" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_e05cab29-220b-413c-94f0-b71a29d670eb" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalFairValue_98358f7b-8a6e-4b60-a3e7-e43976295422" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.gibraltar1.com/role/EquityBasedCompensationCashPaidtoSettleLiabilityAwardsDetails" xlink:type="simple" xlink:href="rock-20231231.xsd#EquityBasedCompensationCashPaidtoSettleLiabilityAwardsDetails"/>
  <link:definitionLink xlink:role="http://www.gibraltar1.com/role/EquityBasedCompensationCashPaidtoSettleLiabilityAwardsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_fc3f7e70-6580-4871-aeef-09699fa0c7a4" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_b0954c83-6bb5-46bb-bcc7-10258c446dc3" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_fc3f7e70-6580-4871-aeef-09699fa0c7a4" xlink:to="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_b0954c83-6bb5-46bb-bcc7-10258c446dc3" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_TitleOfIndividualAxis_33428ff6-2bfc-4ca6-9bbe-bee343c56127" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_TitleOfIndividualAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_b0954c83-6bb5-46bb-bcc7-10258c446dc3" xlink:to="loc_srt_TitleOfIndividualAxis_33428ff6-2bfc-4ca6-9bbe-bee343c56127" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_33428ff6-2bfc-4ca6-9bbe-bee343c56127_default" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_TitleOfIndividualWithRelationshipToEntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_TitleOfIndividualAxis_33428ff6-2bfc-4ca6-9bbe-bee343c56127" xlink:to="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_33428ff6-2bfc-4ca6-9bbe-bee343c56127_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_565db0a2-6ac5-4efb-a884-29d2334732e2" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_TitleOfIndividualWithRelationshipToEntityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_TitleOfIndividualAxis_33428ff6-2bfc-4ca6-9bbe-bee343c56127" xlink:to="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_565db0a2-6ac5-4efb-a884-29d2334732e2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ManagementMember_d8ac0685-c69d-4678-b95a-d1c8302f5cb9" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ManagementMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_TitleOfIndividualWithRelationshipToEntityDomain_565db0a2-6ac5-4efb-a884-29d2334732e2" xlink:to="loc_srt_ManagementMember_d8ac0685-c69d-4678-b95a-d1c8302f5cb9" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AwardTypeAxis_ed8ae0ff-505b-4594-aff4-aafe11f7cd71" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AwardTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_b0954c83-6bb5-46bb-bcc7-10258c446dc3" xlink:to="loc_us-gaap_AwardTypeAxis_ed8ae0ff-505b-4594-aff4-aafe11f7cd71" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_ed8ae0ff-505b-4594-aff4-aafe11f7cd71_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AwardTypeAxis_ed8ae0ff-505b-4594-aff4-aafe11f7cd71" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_ed8ae0ff-505b-4594-aff4-aafe11f7cd71_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_70cb8c90-e034-499c-ab64-861f63dc36e9" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AwardTypeAxis_ed8ae0ff-505b-4594-aff4-aafe11f7cd71" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_70cb8c90-e034-499c-ab64-861f63dc36e9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedStockUnitsRSUMember_4e208aaf-649d-41b1-b259-2f185360b177" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RestrictedStockUnitsRSUMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_70cb8c90-e034-499c-ab64-861f63dc36e9" xlink:to="loc_us-gaap_RestrictedStockUnitsRSUMember_4e208aaf-649d-41b1-b259-2f185360b177" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_cf152248-ca51-465c-b06d-1b715d57aef6" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_b0954c83-6bb5-46bb-bcc7-10258c446dc3" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_cf152248-ca51-465c-b06d-1b715d57aef6" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_cf152248-ca51-465c-b06d-1b715d57aef6_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_cf152248-ca51-465c-b06d-1b715d57aef6" xlink:to="loc_us-gaap_EquityComponentDomain_cf152248-ca51-465c-b06d-1b715d57aef6_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_1fdd4821-8e0e-4b73-9360-26ddf75006ed" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_cf152248-ca51-465c-b06d-1b715d57aef6" xlink:to="loc_us-gaap_EquityComponentDomain_1fdd4821-8e0e-4b73-9360-26ddf75006ed" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_ManagementStockPurchasePlanMember_bd06ac80-caa8-412a-b658-de8938385027" xlink:href="rock-20231231.xsd#rock_ManagementStockPurchasePlanMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_1fdd4821-8e0e-4b73-9360-26ddf75006ed" xlink:to="loc_rock_ManagementStockPurchasePlanMember_bd06ac80-caa8-412a-b658-de8938385027" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsGranted_e692a4a6-5e47-43fc-8155-496dc5c2584a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsGranted"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_fc3f7e70-6580-4871-aeef-09699fa0c7a4" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsGranted_e692a4a6-5e47-43fc-8155-496dc5c2584a" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsOutstandingNumber_4b490c7b-83f7-4edd-9d1b-7e6cb46c0d67" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsOutstandingNumber"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_fc3f7e70-6580-4871-aeef-09699fa0c7a4" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsOutstandingNumber_4b490c7b-83f7-4edd-9d1b-7e6cb46c0d67" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsShareBasedLiabilitiesPaid_faa7fdf9-22ec-43d2-ae9b-c49a58494133" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsShareBasedLiabilitiesPaid"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_fc3f7e70-6580-4871-aeef-09699fa0c7a4" xlink:to="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsShareBasedLiabilitiesPaid_faa7fdf9-22ec-43d2-ae9b-c49a58494133" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_ManagementStockPurchasePlanCompensationExpense_a62eeb27-01c3-4bab-b4cc-e7d19146f873" xlink:href="rock-20231231.xsd#rock_ManagementStockPurchasePlanCompensationExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_fc3f7e70-6580-4871-aeef-09699fa0c7a4" xlink:to="loc_rock_ManagementStockPurchasePlanCompensationExpense_a62eeb27-01c3-4bab-b4cc-e7d19146f873" xlink:type="arc" order="3"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.gibraltar1.com/role/FairValueMeasurementsNarrativeDetails" xlink:type="simple" xlink:href="rock-20231231.xsd#FairValueMeasurementsNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.gibraltar1.com/role/FairValueMeasurementsNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ExtinguishmentOfDebtLineItems_4dc62bba-c9ec-4fc1-8a96-03f37a3e809c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ExtinguishmentOfDebtLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfExtinguishmentOfDebtTable_9cd8596f-6c4d-4a59-8f8f-c7608e154d9c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfExtinguishmentOfDebtTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_ExtinguishmentOfDebtLineItems_4dc62bba-c9ec-4fc1-8a96-03f37a3e809c" xlink:to="loc_us-gaap_ScheduleOfExtinguishmentOfDebtTable_9cd8596f-6c4d-4a59-8f8f-c7608e154d9c" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityAxis_b7450d6b-d979-43de-9e68-0575b8f74542" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CreditFacilityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfExtinguishmentOfDebtTable_9cd8596f-6c4d-4a59-8f8f-c7608e154d9c" xlink:to="loc_us-gaap_CreditFacilityAxis_b7450d6b-d979-43de-9e68-0575b8f74542" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_b7450d6b-d979-43de-9e68-0575b8f74542_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_CreditFacilityAxis_b7450d6b-d979-43de-9e68-0575b8f74542" xlink:to="loc_us-gaap_CreditFacilityDomain_b7450d6b-d979-43de-9e68-0575b8f74542_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CreditFacilityDomain_6e195f57-330c-491b-819f-cc2f3f8dc7a7" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CreditFacilityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_CreditFacilityAxis_b7450d6b-d979-43de-9e68-0575b8f74542" xlink:to="loc_us-gaap_CreditFacilityDomain_6e195f57-330c-491b-819f-cc2f3f8dc7a7" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevolvingCreditFacilityMember_016d88e7-b443-4821-acde-5da2822fd766" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RevolvingCreditFacilityMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CreditFacilityDomain_6e195f57-330c-491b-819f-cc2f3f8dc7a7" xlink:to="loc_us-gaap_RevolvingCreditFacilityMember_016d88e7-b443-4821-acde-5da2822fd766" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentAxis_31ddfbbf-f34d-4f99-8a99-8b4dd93369fe" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfExtinguishmentOfDebtTable_9cd8596f-6c4d-4a59-8f8f-c7608e154d9c" xlink:to="loc_us-gaap_DebtInstrumentAxis_31ddfbbf-f34d-4f99-8a99-8b4dd93369fe" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_31ddfbbf-f34d-4f99-8a99-8b4dd93369fe_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DebtInstrumentAxis_31ddfbbf-f34d-4f99-8a99-8b4dd93369fe" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_31ddfbbf-f34d-4f99-8a99-8b4dd93369fe_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentNameDomain_609fa5f5-5560-4240-a34f-e36dfb18bf05" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DebtInstrumentNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DebtInstrumentAxis_31ddfbbf-f34d-4f99-8a99-8b4dd93369fe" xlink:to="loc_us-gaap_DebtInstrumentNameDomain_609fa5f5-5560-4240-a34f-e36dfb18bf05" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_SeniorCreditAgreementMember_da48807d-89a4-4288-8d52-839a88ac76b0" xlink:href="rock-20231231.xsd#rock_SeniorCreditAgreementMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DebtInstrumentNameDomain_609fa5f5-5560-4240-a34f-e36dfb18bf05" xlink:to="loc_rock_SeniorCreditAgreementMember_da48807d-89a4-4288-8d52-839a88ac76b0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LongTermDebt_de6761b4-5dda-438e-bd78-eede68b1b52f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LongTermDebt"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ExtinguishmentOfDebtLineItems_4dc62bba-c9ec-4fc1-8a96-03f37a3e809c" xlink:to="loc_us-gaap_LongTermDebt_de6761b4-5dda-438e-bd78-eede68b1b52f" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.gibraltar1.com/role/DiscontinuedOperationsNarrativeDetails" xlink:type="simple" xlink:href="rock-20231231.xsd#DiscontinuedOperationsNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.gibraltar1.com/role/DiscontinuedOperationsNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_1024dc97-0372-4083-aeb2-0a298ddc434e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable_54dcab87-580a-473b-abc4-2777a9cc00e3" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_1024dc97-0372-4083-aeb2-0a298ddc434e" xlink:to="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable_54dcab87-580a-473b-abc4-2777a9cc00e3" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupClassificationAxis_2112dbcc-8370-439a-8899-a5152ff63b67" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DisposalGroupClassificationAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable_54dcab87-580a-473b-abc4-2777a9cc00e3" xlink:to="loc_us-gaap_DisposalGroupClassificationAxis_2112dbcc-8370-439a-8899-a5152ff63b67" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupClassificationDomain_2112dbcc-8370-439a-8899-a5152ff63b67_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DisposalGroupClassificationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_DisposalGroupClassificationAxis_2112dbcc-8370-439a-8899-a5152ff63b67" xlink:to="loc_us-gaap_DisposalGroupClassificationDomain_2112dbcc-8370-439a-8899-a5152ff63b67_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupClassificationDomain_ce31f966-1bde-44ee-b1be-fdae915368e1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DisposalGroupClassificationDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_DisposalGroupClassificationAxis_2112dbcc-8370-439a-8899-a5152ff63b67" xlink:to="loc_us-gaap_DisposalGroupClassificationDomain_ce31f966-1bde-44ee-b1be-fdae915368e1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DiscontinuedOperationsDisposedOfBySaleMember_da21b248-fce8-4e7a-9c94-de4e6e29e547" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DiscontinuedOperationsDisposedOfBySaleMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisposalGroupClassificationDomain_ce31f966-1bde-44ee-b1be-fdae915368e1" xlink:to="loc_us-gaap_DiscontinuedOperationsDisposedOfBySaleMember_da21b248-fce8-4e7a-9c94-de4e6e29e547" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupDisposedOfBySaleNotDiscontinuedOperationsMember_c7d197f6-67ae-4f88-aa38-d598007fb726" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DisposalGroupDisposedOfBySaleNotDiscontinuedOperationsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisposalGroupClassificationDomain_ce31f966-1bde-44ee-b1be-fdae915368e1" xlink:to="loc_us-gaap_DisposalGroupDisposedOfBySaleNotDiscontinuedOperationsMember_c7d197f6-67ae-4f88-aa38-d598007fb726" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_b1c78825-03a5-4a89-a19b-e39edce9f94d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsTable_54dcab87-580a-473b-abc4-2777a9cc00e3" xlink:to="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_b1c78825-03a5-4a89-a19b-e39edce9f94d" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_b1c78825-03a5-4a89-a19b-e39edce9f94d_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_b1c78825-03a5-4a89-a19b-e39edce9f94d" xlink:to="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_b1c78825-03a5-4a89-a19b-e39edce9f94d_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_d5272add-b46a-4e81-be56-d91daeea3a0b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsAxis_b1c78825-03a5-4a89-a19b-e39edce9f94d" xlink:to="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_d5272add-b46a-4e81-be56-d91daeea3a0b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_IndustrialBusinessSegmentMember_b3b09df8-cbc4-4846-8ae8-4b9dcefcccf2" xlink:href="rock-20231231.xsd#rock_IndustrialBusinessSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_d5272add-b46a-4e81-be56-d91daeea3a0b" xlink:to="loc_rock_IndustrialBusinessSegmentMember_b3b09df8-cbc4-4846-8ae8-4b9dcefcccf2" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_JapanBasedSolarRackingBusinessMember_e10dbfe5-aab5-4cd2-994e-37eaa21b000b" xlink:href="rock-20231231.xsd#rock_JapanBasedSolarRackingBusinessMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsNameDomain_d5272add-b46a-4e81-be56-d91daeea3a0b" xlink:to="loc_rock_JapanBasedSolarRackingBusinessMember_e10dbfe5-aab5-4cd2-994e-37eaa21b000b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationConsideration_4d6eb6bc-7fd8-4333-9966-b9cbac1df49b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DisposalGroupIncludingDiscontinuedOperationConsideration"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_1024dc97-0372-4083-aeb2-0a298ddc434e" xlink:to="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationConsideration_4d6eb6bc-7fd8-4333-9966-b9cbac1df49b" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NoncashOrPartNoncashDivestitureAmountOfConsiderationReceived1_34084df2-16ce-47a8-9909-a9b5799dd1c5" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_NoncashOrPartNoncashDivestitureAmountOfConsiderationReceived1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_1024dc97-0372-4083-aeb2-0a298ddc434e" xlink:to="loc_us-gaap_NoncashOrPartNoncashDivestitureAmountOfConsiderationReceived1_34084df2-16ce-47a8-9909-a9b5799dd1c5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DiscontinuedOperationGainLossFromDisposalOfDiscontinuedOperationBeforeIncomeTax_ace04ff4-4a3a-4594-8fcd-c274c8f3a50e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DiscontinuedOperationGainLossFromDisposalOfDiscontinuedOperationBeforeIncomeTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_1024dc97-0372-4083-aeb2-0a298ddc434e" xlink:to="loc_us-gaap_DiscontinuedOperationGainLossFromDisposalOfDiscontinuedOperationBeforeIncomeTax_ace04ff4-4a3a-4594-8fcd-c274c8f3a50e" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GainLossOnSaleOfBusiness_6d810ac6-a41e-4953-b627-e2f5ed9a809a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_GainLossOnSaleOfBusiness"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_1024dc97-0372-4083-aeb2-0a298ddc434e" xlink:to="loc_us-gaap_GainLossOnSaleOfBusiness_6d810ac6-a41e-4953-b627-e2f5ed9a809a" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DiscontinuedOperationIncomeLossFromDiscontinuedOperationBeforeIncomeTax_1cfcd7cc-9ada-46cf-9d80-8450e160219f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DiscontinuedOperationIncomeLossFromDiscontinuedOperationBeforeIncomeTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_1024dc97-0372-4083-aeb2-0a298ddc434e" xlink:to="loc_us-gaap_DiscontinuedOperationIncomeLossFromDiscontinuedOperationBeforeIncomeTax_1cfcd7cc-9ada-46cf-9d80-8450e160219f" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationRevenue_49f139ea-acfd-4b23-9f97-f99015e87837" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DisposalGroupIncludingDiscontinuedOperationRevenue"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_1024dc97-0372-4083-aeb2-0a298ddc434e" xlink:to="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationRevenue_49f139ea-acfd-4b23-9f97-f99015e87837" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationOperatingExpense_14e65fd1-462a-4943-a2e1-545e9700681b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DisposalGroupIncludingDiscontinuedOperationOperatingExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_1024dc97-0372-4083-aeb2-0a298ddc434e" xlink:to="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationOperatingExpense_14e65fd1-462a-4943-a2e1-545e9700681b" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DiscontinuedOperationGainLossOnDisposalOfDiscontinuedOperationNetOfTax_632a49ae-00bd-4055-8410-fed36ba7c9af" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DiscontinuedOperationGainLossOnDisposalOfDiscontinuedOperationNetOfTax"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_1024dc97-0372-4083-aeb2-0a298ddc434e" xlink:to="loc_us-gaap_DiscontinuedOperationGainLossOnDisposalOfDiscontinuedOperationNetOfTax_632a49ae-00bd-4055-8410-fed36ba7c9af" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromDivestitureOfInterestInConsolidatedSubsidiaries_a2bdcb71-6ffd-48b4-8133-70f3db6a320a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ProceedsFromDivestitureOfInterestInConsolidatedSubsidiaries"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_1024dc97-0372-4083-aeb2-0a298ddc434e" xlink:to="loc_us-gaap_ProceedsFromDivestitureOfInterestInConsolidatedSubsidiaries_a2bdcb71-6ffd-48b4-8133-70f3db6a320a" xlink:type="arc" order="8"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_DiscontinuedOperationGainLossOnDisposalStatementOfIncomeOrComprehensiveIncomeExtensibleEnumerationNotDisclosedFlag_8414ecdc-f4a3-4a15-a1db-79d54bd24d1b" xlink:href="rock-20231231.xsd#rock_DiscontinuedOperationGainLossOnDisposalStatementOfIncomeOrComprehensiveIncomeExtensibleEnumerationNotDisclosedFlag"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementBalanceSheetAndAdditionalDisclosuresByDisposalGroupsIncludingDiscontinuedOperationsLineItems_1024dc97-0372-4083-aeb2-0a298ddc434e" xlink:to="loc_rock_DiscontinuedOperationGainLossOnDisposalStatementOfIncomeOrComprehensiveIncomeExtensibleEnumerationNotDisclosedFlag_8414ecdc-f4a3-4a15-a1db-79d54bd24d1b" xlink:type="arc" order="9"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.gibraltar1.com/role/ExitActivityCostsandAssetImpairmentsScheduleOfAssetImpairmentChargesRelatedToRestructuringActivitiesDetails" xlink:type="simple" xlink:href="rock-20231231.xsd#ExitActivityCostsandAssetImpairmentsScheduleOfAssetImpairmentChargesRelatedToRestructuringActivitiesDetails"/>
  <link:definitionLink xlink:role="http://www.gibraltar1.com/role/ExitActivityCostsandAssetImpairmentsScheduleOfAssetImpairmentChargesRelatedToRestructuringActivitiesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringCostAndReserveLineItems_1caf2502-9552-43e8-b92a-e1be99fc8654" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RestructuringCostAndReserveLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_4e64e738-d60f-4199-888e-43a53571e016" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfRestructuringAndRelatedCostsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RestructuringCostAndReserveLineItems_1caf2502-9552-43e8-b92a-e1be99fc8654" xlink:to="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_4e64e738-d60f-4199-888e-43a53571e016" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_5c377ca3-0641-4047-b088-c9c32fda711f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_4e64e738-d60f-4199-888e-43a53571e016" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_5c377ca3-0641-4047-b088-c9c32fda711f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_5c377ca3-0641-4047-b088-c9c32fda711f_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_5c377ca3-0641-4047-b088-c9c32fda711f" xlink:to="loc_us-gaap_SegmentDomain_5c377ca3-0641-4047-b088-c9c32fda711f_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_5dbfdb46-fc2e-4210-a73a-520ecbb1a00a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_5c377ca3-0641-4047-b088-c9c32fda711f" xlink:to="loc_us-gaap_SegmentDomain_5dbfdb46-fc2e-4210-a73a-520ecbb1a00a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_RenewablesMember_accaca7a-2c40-4c8c-afab-93bed73696bf" xlink:href="rock-20231231.xsd#rock_RenewablesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_5dbfdb46-fc2e-4210-a73a-520ecbb1a00a" xlink:to="loc_rock_RenewablesMember_accaca7a-2c40-4c8c-afab-93bed73696bf" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_ResidentialMember_2c0e905b-9b39-4d97-aa9b-eaf3f4fd058e" xlink:href="rock-20231231.xsd#rock_ResidentialMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_5dbfdb46-fc2e-4210-a73a-520ecbb1a00a" xlink:to="loc_rock_ResidentialMember_2c0e905b-9b39-4d97-aa9b-eaf3f4fd058e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_InfrastructureMember_6030b759-e115-4dde-8af3-05d0d7ed0acd" xlink:href="rock-20231231.xsd#rock_InfrastructureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_5dbfdb46-fc2e-4210-a73a-520ecbb1a00a" xlink:to="loc_rock_InfrastructureMember_6030b759-e115-4dde-8af3-05d0d7ed0acd" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_AgtechMember_0308c06a-97ae-4f5a-b8a7-5fef76115ea7" xlink:href="rock-20231231.xsd#rock_AgtechMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_5dbfdb46-fc2e-4210-a73a-520ecbb1a00a" xlink:to="loc_rock_AgtechMember_0308c06a-97ae-4f5a-b8a7-5fef76115ea7" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsAxis_1495858a-affe-42a8-9316-09e14d5b0fb5" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ConsolidationItemsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_4e64e738-d60f-4199-888e-43a53571e016" xlink:to="loc_srt_ConsolidationItemsAxis_1495858a-affe-42a8-9316-09e14d5b0fb5" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_1495858a-affe-42a8-9316-09e14d5b0fb5_default" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidationItemsAxis_1495858a-affe-42a8-9316-09e14d5b0fb5" xlink:to="loc_srt_ConsolidationItemsDomain_1495858a-affe-42a8-9316-09e14d5b0fb5_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_1c26d66e-abb4-4d62-8806-c962d3de4e52" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidationItemsAxis_1495858a-affe-42a8-9316-09e14d5b0fb5" xlink:to="loc_srt_ConsolidationItemsDomain_1c26d66e-abb4-4d62-8806-c962d3de4e52" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingSegmentsMember_4d936b9e-343a-4c9b-944e-dc181afdd1d0" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OperatingSegmentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_1c26d66e-abb4-4d62-8806-c962d3de4e52" xlink:to="loc_us-gaap_OperatingSegmentsMember_4d936b9e-343a-4c9b-944e-dc181afdd1d0" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CorporateNonSegmentMember_e14e914e-5b80-412d-9921-0db40d14682c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CorporateNonSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_1c26d66e-abb4-4d62-8806-c962d3de4e52" xlink:to="loc_us-gaap_CorporateNonSegmentMember_e14e914e-5b80-412d-9921-0db40d14682c" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BusinessExitCosts1_a5a08985-b15d-4fb5-b8c7-04e30deb2e9d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_BusinessExitCosts1"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringCostAndReserveLineItems_1caf2502-9552-43e8-b92a-e1be99fc8654" xlink:to="loc_us-gaap_BusinessExitCosts1_a5a08985-b15d-4fb5-b8c7-04e30deb2e9d" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringSettlementAndImpairmentProvisions_a57023f4-02b2-417d-bd5f-ec5d3bebc8c1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RestructuringSettlementAndImpairmentProvisions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringCostAndReserveLineItems_1caf2502-9552-43e8-b92a-e1be99fc8654" xlink:to="loc_us-gaap_RestructuringSettlementAndImpairmentProvisions_a57023f4-02b2-417d-bd5f-ec5d3bebc8c1" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringCharges_fe29091a-6309-4515-ab93-6eb7bb85e87f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RestructuringCharges"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringCostAndReserveLineItems_1caf2502-9552-43e8-b92a-e1be99fc8654" xlink:to="loc_us-gaap_RestructuringCharges_fe29091a-6309-4515-ab93-6eb7bb85e87f" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.gibraltar1.com/role/ExitActivityCostsandAssetImpairmentsSummaryOfExitActivityCostsAndAssetImpairmentsRecordedintheConsolidatedStatementsofOperationsDetails" xlink:type="simple" xlink:href="rock-20231231.xsd#ExitActivityCostsandAssetImpairmentsSummaryOfExitActivityCostsAndAssetImpairmentsRecordedintheConsolidatedStatementsofOperationsDetails"/>
  <link:definitionLink xlink:role="http://www.gibraltar1.com/role/ExitActivityCostsandAssetImpairmentsSummaryOfExitActivityCostsAndAssetImpairmentsRecordedintheConsolidatedStatementsofOperationsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringCostAndReserveLineItems_fc577a81-ec33-440b-973d-7d37957aef93" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RestructuringCostAndReserveLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_24bb2500-a9a1-4d9e-8de7-ee815334d617" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfRestructuringAndRelatedCostsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RestructuringCostAndReserveLineItems_fc577a81-ec33-440b-973d-7d37957aef93" xlink:to="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_24bb2500-a9a1-4d9e-8de7-ee815334d617" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringCostAndReserveAxis_e2145453-6033-40f2-8b7b-a3509f165b14" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RestructuringCostAndReserveAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRestructuringAndRelatedCostsTable_24bb2500-a9a1-4d9e-8de7-ee815334d617" xlink:to="loc_us-gaap_RestructuringCostAndReserveAxis_e2145453-6033-40f2-8b7b-a3509f165b14" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfRestructuringDomain_e2145453-6033-40f2-8b7b-a3509f165b14_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TypeOfRestructuringDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_RestructuringCostAndReserveAxis_e2145453-6033-40f2-8b7b-a3509f165b14" xlink:to="loc_us-gaap_TypeOfRestructuringDomain_e2145453-6033-40f2-8b7b-a3509f165b14_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TypeOfRestructuringDomain_0c94234f-c9ad-4c88-82f3-81fb0f0800e3" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TypeOfRestructuringDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_RestructuringCostAndReserveAxis_e2145453-6033-40f2-8b7b-a3509f165b14" xlink:to="loc_us-gaap_TypeOfRestructuringDomain_0c94234f-c9ad-4c88-82f3-81fb0f0800e3" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CostOfSalesMember_ccf390fa-dd06-41dc-9803-c7806e72978c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CostOfSalesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TypeOfRestructuringDomain_0c94234f-c9ad-4c88-82f3-81fb0f0800e3" xlink:to="loc_us-gaap_CostOfSalesMember_ccf390fa-dd06-41dc-9803-c7806e72978c" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_SellingGeneralAndAdministrativeExpenseMember_7a41adfd-ac72-4a37-9144-da5112a340ff" xlink:href="rock-20231231.xsd#rock_SellingGeneralAndAdministrativeExpenseMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TypeOfRestructuringDomain_0c94234f-c9ad-4c88-82f3-81fb0f0800e3" xlink:to="loc_rock_SellingGeneralAndAdministrativeExpenseMember_7a41adfd-ac72-4a37-9144-da5112a340ff" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestructuringCharges_71ec9402-7c1f-4b1b-add6-b86489742414" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RestructuringCharges"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RestructuringCostAndReserveLineItems_fc577a81-ec33-440b-973d-7d37957aef93" xlink:to="loc_us-gaap_RestructuringCharges_71ec9402-7c1f-4b1b-add6-b86489742414" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.gibraltar1.com/role/IncomeTaxesBenefitofProvisionforIncomeTaxesDetails" xlink:type="simple" xlink:href="rock-20231231.xsd#IncomeTaxesBenefitofProvisionforIncomeTaxesDetails"/>
  <link:definitionLink xlink:role="http://www.gibraltar1.com/role/IncomeTaxesBenefitofProvisionforIncomeTaxesDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxContingencyLineItems_18cd1697-cd6a-4b42-8549-c4c6ea2d14fb" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeTaxContingencyLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxContingencyTable_a7979e3f-e0a7-471d-8147-39d6281d6b6a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeTaxContingencyTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_IncomeTaxContingencyLineItems_18cd1697-cd6a-4b42-8549-c4c6ea2d14fb" xlink:to="loc_us-gaap_IncomeTaxContingencyTable_a7979e3f-e0a7-471d-8147-39d6281d6b6a" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementOperatingActivitiesSegmentAxis_824c0d56-8929-4d14-9474-3c8a81a262a5" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementOperatingActivitiesSegmentAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_IncomeTaxContingencyTable_a7979e3f-e0a7-471d-8147-39d6281d6b6a" xlink:to="loc_us-gaap_StatementOperatingActivitiesSegmentAxis_824c0d56-8929-4d14-9474-3c8a81a262a5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentOperatingActivitiesDomain_824c0d56-8929-4d14-9474-3c8a81a262a5_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SegmentOperatingActivitiesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementOperatingActivitiesSegmentAxis_824c0d56-8929-4d14-9474-3c8a81a262a5" xlink:to="loc_us-gaap_SegmentOperatingActivitiesDomain_824c0d56-8929-4d14-9474-3c8a81a262a5_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentOperatingActivitiesDomain_98d32941-2485-4413-9eee-e366a7a5c1d9" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SegmentOperatingActivitiesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementOperatingActivitiesSegmentAxis_824c0d56-8929-4d14-9474-3c8a81a262a5" xlink:to="loc_us-gaap_SegmentOperatingActivitiesDomain_98d32941-2485-4413-9eee-e366a7a5c1d9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentContinuingOperationsMember_18350396-c0ef-469c-8126-c1c2d8c49ca7" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SegmentContinuingOperationsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentOperatingActivitiesDomain_98d32941-2485-4413-9eee-e366a7a5c1d9" xlink:to="loc_us-gaap_SegmentContinuingOperationsMember_18350396-c0ef-469c-8126-c1c2d8c49ca7" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CurrentIncomeTaxExpenseBenefitContinuingOperationsAbstract_8adfd833-5fef-4f14-a655-d2bdcf900e68" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CurrentIncomeTaxExpenseBenefitContinuingOperationsAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxContingencyLineItems_18cd1697-cd6a-4b42-8549-c4c6ea2d14fb" xlink:to="loc_us-gaap_CurrentIncomeTaxExpenseBenefitContinuingOperationsAbstract_8adfd833-5fef-4f14-a655-d2bdcf900e68" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CurrentFederalTaxExpenseBenefit_3876fecc-7068-4198-9eb1-0fa8af7157f4" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CurrentFederalTaxExpenseBenefit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CurrentIncomeTaxExpenseBenefitContinuingOperationsAbstract_8adfd833-5fef-4f14-a655-d2bdcf900e68" xlink:to="loc_us-gaap_CurrentFederalTaxExpenseBenefit_3876fecc-7068-4198-9eb1-0fa8af7157f4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CurrentStateAndLocalTaxExpenseBenefit_786355d0-2540-49ae-87e2-4baa9ae30109" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CurrentStateAndLocalTaxExpenseBenefit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CurrentIncomeTaxExpenseBenefitContinuingOperationsAbstract_8adfd833-5fef-4f14-a655-d2bdcf900e68" xlink:to="loc_us-gaap_CurrentStateAndLocalTaxExpenseBenefit_786355d0-2540-49ae-87e2-4baa9ae30109" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CurrentForeignTaxExpenseBenefit_59b24311-35f8-4492-86f8-5e295724251a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CurrentForeignTaxExpenseBenefit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CurrentIncomeTaxExpenseBenefitContinuingOperationsAbstract_8adfd833-5fef-4f14-a655-d2bdcf900e68" xlink:to="loc_us-gaap_CurrentForeignTaxExpenseBenefit_59b24311-35f8-4492-86f8-5e295724251a" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CurrentIncomeTaxExpenseBenefit_7a06b436-819c-4e24-8e94-222bcc24e9f8" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CurrentIncomeTaxExpenseBenefit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_CurrentIncomeTaxExpenseBenefitContinuingOperationsAbstract_8adfd833-5fef-4f14-a655-d2bdcf900e68" xlink:to="loc_us-gaap_CurrentIncomeTaxExpenseBenefit_7a06b436-819c-4e24-8e94-222bcc24e9f8" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredIncomeTaxExpenseBenefitContinuingOperationsAbstract_3d819d9a-9b40-4f30-93d5-a5eb6e061761" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DeferredIncomeTaxExpenseBenefitContinuingOperationsAbstract"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxContingencyLineItems_18cd1697-cd6a-4b42-8549-c4c6ea2d14fb" xlink:to="loc_us-gaap_DeferredIncomeTaxExpenseBenefitContinuingOperationsAbstract_3d819d9a-9b40-4f30-93d5-a5eb6e061761" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredFederalIncomeTaxExpenseBenefit_106bbb6d-abe3-465a-b9c8-89d6f9e6311f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DeferredFederalIncomeTaxExpenseBenefit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DeferredIncomeTaxExpenseBenefitContinuingOperationsAbstract_3d819d9a-9b40-4f30-93d5-a5eb6e061761" xlink:to="loc_us-gaap_DeferredFederalIncomeTaxExpenseBenefit_106bbb6d-abe3-465a-b9c8-89d6f9e6311f" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredStateAndLocalIncomeTaxExpenseBenefit_e383f86b-8688-4a76-a9db-6d827fb41123" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DeferredStateAndLocalIncomeTaxExpenseBenefit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DeferredIncomeTaxExpenseBenefitContinuingOperationsAbstract_3d819d9a-9b40-4f30-93d5-a5eb6e061761" xlink:to="loc_us-gaap_DeferredStateAndLocalIncomeTaxExpenseBenefit_e383f86b-8688-4a76-a9db-6d827fb41123" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredForeignIncomeTaxExpenseBenefit_fb79ecff-2305-48d7-b048-01d6818fffd1" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DeferredForeignIncomeTaxExpenseBenefit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DeferredIncomeTaxExpenseBenefitContinuingOperationsAbstract_3d819d9a-9b40-4f30-93d5-a5eb6e061761" xlink:to="loc_us-gaap_DeferredForeignIncomeTaxExpenseBenefit_fb79ecff-2305-48d7-b048-01d6818fffd1" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredIncomeTaxExpenseBenefit_2e360ab1-d511-4e28-92cf-eba581399a6d" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DeferredIncomeTaxExpenseBenefit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DeferredIncomeTaxExpenseBenefitContinuingOperationsAbstract_3d819d9a-9b40-4f30-93d5-a5eb6e061761" xlink:to="loc_us-gaap_DeferredIncomeTaxExpenseBenefit_2e360ab1-d511-4e28-92cf-eba581399a6d" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit_340e2c40-de63-45ac-a577-c750f8b890be" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeTaxExpenseBenefit"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxContingencyLineItems_18cd1697-cd6a-4b42-8549-c4c6ea2d14fb" xlink:to="loc_us-gaap_IncomeTaxExpenseBenefit_340e2c40-de63-45ac-a577-c750f8b890be" xlink:type="arc" order="2"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.gibraltar1.com/role/IncomeTaxesNarrativeDetails" xlink:type="simple" xlink:href="rock-20231231.xsd#IncomeTaxesNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.gibraltar1.com/role/IncomeTaxesNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLossCarryforwardsLineItems_e640cd3a-e6f7-436f-ace9-20e03ee0df61" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OperatingLossCarryforwardsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLossCarryforwardsTable_f34829bf-a45f-4c03-b2d4-68381754c0cd" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OperatingLossCarryforwardsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_OperatingLossCarryforwardsLineItems_e640cd3a-e6f7-436f-ace9-20e03ee0df61" xlink:to="loc_us-gaap_OperatingLossCarryforwardsTable_f34829bf-a45f-4c03-b2d4-68381754c0cd" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxAuthorityAxis_70253ee0-f797-4a80-882b-4ab789de1360" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeTaxAuthorityAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_OperatingLossCarryforwardsTable_f34829bf-a45f-4c03-b2d4-68381754c0cd" xlink:to="loc_us-gaap_IncomeTaxAuthorityAxis_70253ee0-f797-4a80-882b-4ab789de1360" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxAuthorityDomain_70253ee0-f797-4a80-882b-4ab789de1360_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeTaxAuthorityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_IncomeTaxAuthorityAxis_70253ee0-f797-4a80-882b-4ab789de1360" xlink:to="loc_us-gaap_IncomeTaxAuthorityDomain_70253ee0-f797-4a80-882b-4ab789de1360_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxAuthorityDomain_32afd428-0fd9-4790-a8ef-47233da739e2" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeTaxAuthorityDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_IncomeTaxAuthorityAxis_70253ee0-f797-4a80-882b-4ab789de1360" xlink:to="loc_us-gaap_IncomeTaxAuthorityDomain_32afd428-0fd9-4790-a8ef-47233da739e2" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DomesticCountryMember_c565d206-e5f2-4b90-a1b5-52eb438703f6" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DomesticCountryMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxAuthorityDomain_32afd428-0fd9-4790-a8ef-47233da739e2" xlink:to="loc_us-gaap_DomesticCountryMember_c565d206-e5f2-4b90-a1b5-52eb438703f6" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StateAndLocalJurisdictionMember_07eb2492-8674-4824-8d00-c234eb27ebea" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StateAndLocalJurisdictionMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxAuthorityDomain_32afd428-0fd9-4790-a8ef-47233da739e2" xlink:to="loc_us-gaap_StateAndLocalJurisdictionMember_07eb2492-8674-4824-8d00-c234eb27ebea" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForeignCountryMember_1086616d-02bc-4f20-b79c-f14530fe639a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ForeignCountryMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeTaxAuthorityDomain_32afd428-0fd9-4790-a8ef-47233da739e2" xlink:to="loc_us-gaap_ForeignCountryMember_1086616d-02bc-4f20-b79c-f14530fe639a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_a2c2ad63-7f91-4465-98e6-bfa751c0321c" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_OperatingLossCarryforwardsTable_f34829bf-a45f-4c03-b2d4-68381754c0cd" xlink:to="loc_srt_RangeAxis_a2c2ad63-7f91-4465-98e6-bfa751c0321c" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_a2c2ad63-7f91-4465-98e6-bfa751c0321c_default" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_a2c2ad63-7f91-4465-98e6-bfa751c0321c" xlink:to="loc_srt_RangeMember_a2c2ad63-7f91-4465-98e6-bfa751c0321c_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_e1867144-82d9-4765-8c23-4255d4c87088" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_a2c2ad63-7f91-4465-98e6-bfa751c0321c" xlink:to="loc_srt_RangeMember_e1867144-82d9-4765-8c23-4255d4c87088" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_bd14872a-d1f9-465c-9ccb-cd69669626f5" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_e1867144-82d9-4765-8c23-4255d4c87088" xlink:to="loc_srt_MinimumMember_bd14872a-d1f9-465c-9ccb-cd69669626f5" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_5c619b60-d5c8-47a4-8850-ae9065ecc8a5" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_e1867144-82d9-4765-8c23-4255d4c87088" xlink:to="loc_srt_MaximumMember_5c619b60-d5c8-47a4-8850-ae9065ecc8a5" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate_e298d464-5c51-4e6c-bb70-63fdcd1150a8" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLossCarryforwardsLineItems_e640cd3a-e6f7-436f-ace9-20e03ee0df61" xlink:to="loc_us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate_e298d464-5c51-4e6c-bb70-63fdcd1150a8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLossCarryforwards_6acd33c0-5502-4a76-8846-09c68a6840cf" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OperatingLossCarryforwards"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLossCarryforwardsLineItems_e640cd3a-e6f7-436f-ace9-20e03ee0df61" xlink:to="loc_us-gaap_OperatingLossCarryforwards_6acd33c0-5502-4a76-8846-09c68a6840cf" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredTaxAssetsOperatingLossCarryforwards_72129f40-6172-427f-a7dd-1fa2f570ca74" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DeferredTaxAssetsOperatingLossCarryforwards"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLossCarryforwardsLineItems_e640cd3a-e6f7-436f-ace9-20e03ee0df61" xlink:to="loc_us-gaap_DeferredTaxAssetsOperatingLossCarryforwards_72129f40-6172-427f-a7dd-1fa2f570ca74" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredTaxLiabilitiesUndistributedForeignEarnings_d4e512ab-10fc-4579-acaf-e3ad0227b3d9" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DeferredTaxLiabilitiesUndistributedForeignEarnings"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLossCarryforwardsLineItems_e640cd3a-e6f7-436f-ace9-20e03ee0df61" xlink:to="loc_us-gaap_DeferredTaxLiabilitiesUndistributedForeignEarnings_d4e512ab-10fc-4579-acaf-e3ad0227b3d9" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_IncomeTaxStatueOfLimitationsExpirationPeriod_139f8bd2-9ccd-4d05-bb88-1905fe15545a" xlink:href="rock-20231231.xsd#rock_IncomeTaxStatueOfLimitationsExpirationPeriod"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLossCarryforwardsLineItems_e640cd3a-e6f7-436f-ace9-20e03ee0df61" xlink:to="loc_rock_IncomeTaxStatueOfLimitationsExpirationPeriod_139f8bd2-9ccd-4d05-bb88-1905fe15545a" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_CapitalLossCarryforward_9de6c1c7-770b-4994-9c95-6c4b7e5d3646" xlink:href="rock-20231231.xsd#rock_CapitalLossCarryforward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLossCarryforwardsLineItems_e640cd3a-e6f7-436f-ace9-20e03ee0df61" xlink:to="loc_rock_CapitalLossCarryforward_9de6c1c7-770b-4994-9c95-6c4b7e5d3646" xlink:type="arc" order="5"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_CapitalLossCarryforwardAmendedReturns_4bf4c400-98b3-4494-9381-87bab7e8f103" xlink:href="rock-20231231.xsd#rock_CapitalLossCarryforwardAmendedReturns"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLossCarryforwardsLineItems_e640cd3a-e6f7-436f-ace9-20e03ee0df61" xlink:to="loc_rock_CapitalLossCarryforwardAmendedReturns_4bf4c400-98b3-4494-9381-87bab7e8f103" xlink:type="arc" order="6"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredTaxAssetsCapitalLossCarryforwards_e4b88adb-a154-4e44-a39e-ea5bfc9f86f0" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DeferredTaxAssetsCapitalLossCarryforwards"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLossCarryforwardsLineItems_e640cd3a-e6f7-436f-ace9-20e03ee0df61" xlink:to="loc_us-gaap_DeferredTaxAssetsCapitalLossCarryforwards_e4b88adb-a154-4e44-a39e-ea5bfc9f86f0" xlink:type="arc" order="7"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestExpense_bdbf4744-e877-4003-88fc-a95dfdbc7bb9" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_OperatingLossCarryforwardsLineItems_e640cd3a-e6f7-436f-ace9-20e03ee0df61" xlink:to="loc_us-gaap_UnrecognizedTaxBenefitsIncomeTaxPenaltiesAndInterestExpense_bdbf4744-e877-4003-88fc-a95dfdbc7bb9" xlink:type="arc" order="8"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.gibraltar1.com/role/IncomeTaxesSummaryofValuationAllowanceDetails" xlink:type="simple" xlink:href="rock-20231231.xsd#IncomeTaxesSummaryofValuationAllowanceDetails"/>
  <link:definitionLink xlink:role="http://www.gibraltar1.com/role/IncomeTaxesSummaryofValuationAllowanceDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_srt_ValuationAndQualifyingAccountsDisclosureLineItems_5b3f00e9-d06e-4a52-a016-858bbae30648" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ValuationAndQualifyingAccountsDisclosureLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ValuationAndQualifyingAccountsDisclosureTable_f39b1869-c198-4433-99de-4c803c502056" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ValuationAndQualifyingAccountsDisclosureTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_srt_ValuationAndQualifyingAccountsDisclosureLineItems_5b3f00e9-d06e-4a52-a016-858bbae30648" xlink:to="loc_srt_ValuationAndQualifyingAccountsDisclosureTable_f39b1869-c198-4433-99de-4c803c502056" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationAllowancesAndReservesTypeAxis_f0265932-fd0c-4651-85ad-e2a2fe94119e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ValuationAllowancesAndReservesTypeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_srt_ValuationAndQualifyingAccountsDisclosureTable_f39b1869-c198-4433-99de-4c803c502056" xlink:to="loc_us-gaap_ValuationAllowancesAndReservesTypeAxis_f0265932-fd0c-4651-85ad-e2a2fe94119e" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationAllowancesAndReservesDomain_f0265932-fd0c-4651-85ad-e2a2fe94119e_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ValuationAllowancesAndReservesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_ValuationAllowancesAndReservesTypeAxis_f0265932-fd0c-4651-85ad-e2a2fe94119e" xlink:to="loc_us-gaap_ValuationAllowancesAndReservesDomain_f0265932-fd0c-4651-85ad-e2a2fe94119e_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationAllowancesAndReservesDomain_f90e8375-1042-4d71-87ed-7dd619e4f4c8" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ValuationAllowancesAndReservesDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_ValuationAllowancesAndReservesTypeAxis_f0265932-fd0c-4651-85ad-e2a2fe94119e" xlink:to="loc_us-gaap_ValuationAllowancesAndReservesDomain_f90e8375-1042-4d71-87ed-7dd619e4f4c8" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationAllowanceOfDeferredTaxAssetsMember_dc7569b2-71ff-4aed-a8d4-917c7fcc4145" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ValuationAllowanceOfDeferredTaxAssetsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_ValuationAllowancesAndReservesDomain_f90e8375-1042-4d71-87ed-7dd619e4f4c8" xlink:to="loc_us-gaap_ValuationAllowanceOfDeferredTaxAssetsMember_dc7569b2-71ff-4aed-a8d4-917c7fcc4145" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MovementInValuationAllowancesAndReservesRollForward_6ab16629-058f-48f0-bff7-646cdb6fd4be" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_MovementInValuationAllowancesAndReservesRollForward"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ValuationAndQualifyingAccountsDisclosureLineItems_5b3f00e9-d06e-4a52-a016-858bbae30648" xlink:to="loc_us-gaap_MovementInValuationAllowancesAndReservesRollForward_6ab16629-058f-48f0-bff7-646cdb6fd4be" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationAllowancesAndReservesBalance_38e82b07-ad24-4c5e-89ea-31319e2bc58a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ValuationAllowancesAndReservesBalance"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MovementInValuationAllowancesAndReservesRollForward_6ab16629-058f-48f0-bff7-646cdb6fd4be" xlink:to="loc_us-gaap_ValuationAllowancesAndReservesBalance_38e82b07-ad24-4c5e-89ea-31319e2bc58a" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationAllowancesAndReservesChargedToCostAndExpense_52e9c5ae-1dd8-45ba-b447-818cbe26107a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ValuationAllowancesAndReservesChargedToCostAndExpense"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MovementInValuationAllowancesAndReservesRollForward_6ab16629-058f-48f0-bff7-646cdb6fd4be" xlink:to="loc_us-gaap_ValuationAllowancesAndReservesChargedToCostAndExpense_52e9c5ae-1dd8-45ba-b447-818cbe26107a" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationAllowancesAndReservesDeductions_7f01b842-21b0-4dfd-bdb3-c3de072ba045" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ValuationAllowancesAndReservesDeductions"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MovementInValuationAllowancesAndReservesRollForward_6ab16629-058f-48f0-bff7-646cdb6fd4be" xlink:to="loc_us-gaap_ValuationAllowancesAndReservesDeductions_7f01b842-21b0-4dfd-bdb3-c3de072ba045" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationAllowancesAndReservesAdjustments_ed2b4f98-53fb-4861-8322-7c51ad0d0ae3" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ValuationAllowancesAndReservesAdjustments"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_MovementInValuationAllowancesAndReservesRollForward_6ab16629-058f-48f0-bff7-646cdb6fd4be" xlink:to="loc_us-gaap_ValuationAllowancesAndReservesAdjustments_ed2b4f98-53fb-4861-8322-7c51ad0d0ae3" xlink:type="arc" order="4"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ValuationAllowancesAndReservesBalance_0e56cdca-1141-4d9f-9b7d-55b23a3a0c3c" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ValuationAllowancesAndReservesBalance"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.gibraltar1.com/role/EarningsperShareNarrativeDetails" xlink:type="simple" xlink:href="rock-20231231.xsd#EarningsperShareNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.gibraltar1.com/role/EarningsperShareNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_bbdfe770-152d-4613-80d7-f9b4d8b0579f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_18a29659-f0e9-4c32-81ed-df91e9c59d70" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_bbdfe770-152d-4613-80d7-f9b4d8b0579f" xlink:to="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_18a29659-f0e9-4c32-81ed-df91e9c59d70" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_8fb2eafc-c13a-4556-adf3-c32a227dce66" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfAntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareTable_18a29659-f0e9-4c32-81ed-df91e9c59d70" xlink:to="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_8fb2eafc-c13a-4556-adf3-c32a227dce66" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesNameDomain_8fb2eafc-c13a-4556-adf3-c32a227dce66_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AntidilutiveSecuritiesNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_8fb2eafc-c13a-4556-adf3-c32a227dce66" xlink:to="loc_us-gaap_AntidilutiveSecuritiesNameDomain_8fb2eafc-c13a-4556-adf3-c32a227dce66_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesNameDomain_86e97376-ba3d-49c3-a07d-60dd90f88853" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AntidilutiveSecuritiesNameDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareByAntidilutiveSecuritiesAxis_8fb2eafc-c13a-4556-adf3-c32a227dce66" xlink:to="loc_us-gaap_AntidilutiveSecuritiesNameDomain_86e97376-ba3d-49c3-a07d-60dd90f88853" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember_f9c92218-10cc-44b8-b0be-01d9d82c4a15" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CommonStockMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesNameDomain_86e97376-ba3d-49c3-a07d-60dd90f88853" xlink:to="loc_us-gaap_CommonStockMember_f9c92218-10cc-44b8-b0be-01d9d82c4a15" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_d31e282d-2191-4520-9cde-42ef9701e776" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareLineItems_bbdfe770-152d-4613-80d7-f9b4d8b0579f" xlink:to="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_d31e282d-2191-4520-9cde-42ef9701e776" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.gibraltar1.com/role/LeasesNarrativeDetails" xlink:type="simple" xlink:href="rock-20231231.xsd#LeasesNarrativeDetails"/>
  <link:definitionLink xlink:role="http://www.gibraltar1.com/role/LeasesNarrativeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeLeaseDescriptionLineItems_ec5cdaee-40f9-4953-93ba-48f41f862f4a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LesseeLeaseDescriptionLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeLeaseDescriptionTable_8f281c19-883d-4008-a95e-f48142993d53" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LesseeLeaseDescriptionTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_ec5cdaee-40f9-4953-93ba-48f41f862f4a" xlink:to="loc_us-gaap_LesseeLeaseDescriptionTable_8f281c19-883d-4008-a95e-f48142993d53" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementEquityComponentsAxis_167923f9-8b54-4159-9b46-0c88cd0be967" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementEquityComponentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LesseeLeaseDescriptionTable_8f281c19-883d-4008-a95e-f48142993d53" xlink:to="loc_us-gaap_StatementEquityComponentsAxis_167923f9-8b54-4159-9b46-0c88cd0be967" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_167923f9-8b54-4159-9b46-0c88cd0be967_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_167923f9-8b54-4159-9b46-0c88cd0be967" xlink:to="loc_us-gaap_EquityComponentDomain_167923f9-8b54-4159-9b46-0c88cd0be967_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain_f4c04e2b-e19e-43b4-9a7c-632c5efebe24" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_EquityComponentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementEquityComponentsAxis_167923f9-8b54-4159-9b46-0c88cd0be967" xlink:to="loc_us-gaap_EquityComponentDomain_f4c04e2b-e19e-43b4-9a7c-632c5efebe24" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetainedEarningsMember_234b749d-11ea-4a56-906c-9fd6008a7156" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RetainedEarningsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_EquityComponentDomain_f4c04e2b-e19e-43b4-9a7c-632c5efebe24" xlink:to="loc_us-gaap_RetainedEarningsMember_234b749d-11ea-4a56-906c-9fd6008a7156" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeAxis_4e2250ce-81dc-4143-9ac5-24071235e810" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_LesseeLeaseDescriptionTable_8f281c19-883d-4008-a95e-f48142993d53" xlink:to="loc_srt_RangeAxis_4e2250ce-81dc-4143-9ac5-24071235e810" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_4e2250ce-81dc-4143-9ac5-24071235e810_default" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_RangeAxis_4e2250ce-81dc-4143-9ac5-24071235e810" xlink:to="loc_srt_RangeMember_4e2250ce-81dc-4143-9ac5-24071235e810_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_RangeMember_62ed0917-93e4-49a5-ab79-58ddb02c7d78" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_RangeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_RangeAxis_4e2250ce-81dc-4143-9ac5-24071235e810" xlink:to="loc_srt_RangeMember_62ed0917-93e4-49a5-ab79-58ddb02c7d78" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MinimumMember_9cd0208f-6fb0-4080-b263-d53804714718" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_MinimumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_62ed0917-93e4-49a5-ab79-58ddb02c7d78" xlink:to="loc_srt_MinimumMember_9cd0208f-6fb0-4080-b263-d53804714718" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_MaximumMember_ccb1837d-0400-4a51-96fa-04acf974efc9" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_MaximumMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_RangeMember_62ed0917-93e4-49a5-ab79-58ddb02c7d78" xlink:to="loc_srt_MaximumMember_ccb1837d-0400-4a51-96fa-04acf974efc9" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseRenewalTerm_c2cfed22-7f38-4a95-82bc-520163b4efec" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LesseeOperatingLeaseRenewalTerm"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_ec5cdaee-40f9-4953-93ba-48f41f862f4a" xlink:to="loc_us-gaap_LesseeOperatingLeaseRenewalTerm_c2cfed22-7f38-4a95-82bc-520163b4efec" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StockholdersEquity_4e85e0c8-be8b-400c-a13c-32a844788db3" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StockholdersEquity"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LesseeLeaseDescriptionLineItems_ec5cdaee-40f9-4953-93ba-48f41f862f4a" xlink:to="loc_us-gaap_StockholdersEquity_4e85e0c8-be8b-400c-a13c-32a844788db3" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.gibraltar1.com/role/SegmentInformationMeasurementsUsedbyManagementtoAssessPerformanceofSegmentsDetails" xlink:type="simple" xlink:href="rock-20231231.xsd#SegmentInformationMeasurementsUsedbyManagementtoAssessPerformanceofSegmentsDetails"/>
  <link:definitionLink xlink:role="http://www.gibraltar1.com/role/SegmentInformationMeasurementsUsedbyManagementtoAssessPerformanceofSegmentsDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingOtherSignificantReconcilingItemLineItems_fda66247-2de6-4dbd-832b-3e6e48682f75" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SegmentReportingOtherSignificantReconcilingItemLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReconciliationOfOtherSignificantReconcilingItemsFromSegmentsToConsolidatedTable_5ef6203e-2b44-4585-839c-e4c88a14d41a" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ReconciliationOfOtherSignificantReconcilingItemsFromSegmentsToConsolidatedTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_SegmentReportingOtherSignificantReconcilingItemLineItems_fda66247-2de6-4dbd-832b-3e6e48682f75" xlink:to="loc_us-gaap_ReconciliationOfOtherSignificantReconcilingItemsFromSegmentsToConsolidatedTable_5ef6203e-2b44-4585-839c-e4c88a14d41a" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_9412af7e-dbd0-41ee-b2fe-4f0bdd90baf4" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ReconciliationOfOtherSignificantReconcilingItemsFromSegmentsToConsolidatedTable_5ef6203e-2b44-4585-839c-e4c88a14d41a" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_9412af7e-dbd0-41ee-b2fe-4f0bdd90baf4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_9412af7e-dbd0-41ee-b2fe-4f0bdd90baf4_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_9412af7e-dbd0-41ee-b2fe-4f0bdd90baf4" xlink:to="loc_us-gaap_SegmentDomain_9412af7e-dbd0-41ee-b2fe-4f0bdd90baf4_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_5688c879-dbb6-4ead-8e5c-d14a200a96e0" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_9412af7e-dbd0-41ee-b2fe-4f0bdd90baf4" xlink:to="loc_us-gaap_SegmentDomain_5688c879-dbb6-4ead-8e5c-d14a200a96e0" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_RenewablesMember_4fb82b1f-67ac-4ce6-8008-4915f09a64d8" xlink:href="rock-20231231.xsd#rock_RenewablesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_5688c879-dbb6-4ead-8e5c-d14a200a96e0" xlink:to="loc_rock_RenewablesMember_4fb82b1f-67ac-4ce6-8008-4915f09a64d8" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_ResidentialMember_c55798f8-2d46-4cc7-a5ff-45bf0f10a70d" xlink:href="rock-20231231.xsd#rock_ResidentialMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_5688c879-dbb6-4ead-8e5c-d14a200a96e0" xlink:to="loc_rock_ResidentialMember_c55798f8-2d46-4cc7-a5ff-45bf0f10a70d" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_AgtechMember_119b36fd-61dc-4cf3-a6db-524520002dcb" xlink:href="rock-20231231.xsd#rock_AgtechMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_5688c879-dbb6-4ead-8e5c-d14a200a96e0" xlink:to="loc_rock_AgtechMember_119b36fd-61dc-4cf3-a6db-524520002dcb" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_InfrastructureMember_7fcda087-52ef-43d5-b24d-48340dae12fe" xlink:href="rock-20231231.xsd#rock_InfrastructureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_5688c879-dbb6-4ead-8e5c-d14a200a96e0" xlink:to="loc_rock_InfrastructureMember_7fcda087-52ef-43d5-b24d-48340dae12fe" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsAxis_0210c990-b017-485f-bcf0-363e6d31dfc7" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ConsolidationItemsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ReconciliationOfOtherSignificantReconcilingItemsFromSegmentsToConsolidatedTable_5ef6203e-2b44-4585-839c-e4c88a14d41a" xlink:to="loc_srt_ConsolidationItemsAxis_0210c990-b017-485f-bcf0-363e6d31dfc7" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_0210c990-b017-485f-bcf0-363e6d31dfc7_default" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_ConsolidationItemsAxis_0210c990-b017-485f-bcf0-363e6d31dfc7" xlink:to="loc_srt_ConsolidationItemsDomain_0210c990-b017-485f-bcf0-363e6d31dfc7_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidationItemsDomain_ec4ef487-b9cf-4ac0-94df-61f23666f238" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_ConsolidationItemsDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_ConsolidationItemsAxis_0210c990-b017-485f-bcf0-363e6d31dfc7" xlink:to="loc_srt_ConsolidationItemsDomain_ec4ef487-b9cf-4ac0-94df-61f23666f238" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingSegmentsMember_beb5def5-7787-472e-b503-b40917d09a14" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OperatingSegmentsMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_ec4ef487-b9cf-4ac0-94df-61f23666f238" xlink:to="loc_us-gaap_OperatingSegmentsMember_beb5def5-7787-472e-b503-b40917d09a14" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CorporateNonSegmentMember_bbb7ec3f-98db-4374-9ddf-267df5f00375" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_CorporateNonSegmentMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_ConsolidationItemsDomain_ec4ef487-b9cf-4ac0-94df-61f23666f238" xlink:to="loc_us-gaap_CorporateNonSegmentMember_bbb7ec3f-98db-4374-9ddf-267df5f00375" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Revenues_1e2f3c7b-7a02-4dff-adc6-fccd5b8ac4dc" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_Revenues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingOtherSignificantReconcilingItemLineItems_fda66247-2de6-4dbd-832b-3e6e48682f75" xlink:to="loc_us-gaap_Revenues_1e2f3c7b-7a02-4dff-adc6-fccd5b8ac4dc" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingIncomeLoss_40fc3fc8-7454-43fa-a89d-f35a4eaf0b74" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_OperatingIncomeLoss"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingOtherSignificantReconcilingItemLineItems_fda66247-2de6-4dbd-832b-3e6e48682f75" xlink:to="loc_us-gaap_OperatingIncomeLoss_40fc3fc8-7454-43fa-a89d-f35a4eaf0b74" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DepreciationDepletionAndAmortization_31219350-b735-480e-86f9-c8be106db493" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DepreciationDepletionAndAmortization"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingOtherSignificantReconcilingItemLineItems_fda66247-2de6-4dbd-832b-3e6e48682f75" xlink:to="loc_us-gaap_DepreciationDepletionAndAmortization_31219350-b735-480e-86f9-c8be106db493" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Assets_25ac6119-15fb-4aa5-ac9c-14dc8bf3e816" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_Assets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingOtherSignificantReconcilingItemLineItems_fda66247-2de6-4dbd-832b-3e6e48682f75" xlink:to="loc_us-gaap_Assets_25ac6119-15fb-4aa5-ac9c-14dc8bf3e816" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_1fb76588-2f39-4bf0-a5e5-0a863230ec3b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_PaymentsToAcquirePropertyPlantAndEquipment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentReportingOtherSignificantReconcilingItemLineItems_fda66247-2de6-4dbd-832b-3e6e48682f75" xlink:to="loc_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_1fb76588-2f39-4bf0-a5e5-0a863230ec3b" xlink:type="arc" order="4"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.gibraltar1.com/role/SegmentInformationNetSalesbyContractTypeDetails" xlink:type="simple" xlink:href="rock-20231231.xsd#SegmentInformationNetSalesbyContractTypeDetails"/>
  <link:definitionLink xlink:role="http://www.gibraltar1.com/role/SegmentInformationNetSalesbyContractTypeDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueLineItems_361b969e-d7c8-47b5-a5be-75ff020060e2" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DisaggregationOfRevenueLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DisaggregationOfRevenueTable_c31b3bac-7a5f-48d8-b2f2-04544fc19178" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_DisaggregationOfRevenueTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_361b969e-d7c8-47b5-a5be-75ff020060e2" xlink:to="loc_us-gaap_DisaggregationOfRevenueTable_c31b3bac-7a5f-48d8-b2f2-04544fc19178" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TimingOfTransferOfGoodOrServiceAxis_9648d05e-54d4-4aa0-a4a3-21be6bae3f81" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TimingOfTransferOfGoodOrServiceAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_c31b3bac-7a5f-48d8-b2f2-04544fc19178" xlink:to="loc_us-gaap_TimingOfTransferOfGoodOrServiceAxis_9648d05e-54d4-4aa0-a4a3-21be6bae3f81" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TimingOfTransferOfGoodOrServiceDomain_9648d05e-54d4-4aa0-a4a3-21be6bae3f81_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TimingOfTransferOfGoodOrServiceDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_TimingOfTransferOfGoodOrServiceAxis_9648d05e-54d4-4aa0-a4a3-21be6bae3f81" xlink:to="loc_us-gaap_TimingOfTransferOfGoodOrServiceDomain_9648d05e-54d4-4aa0-a4a3-21be6bae3f81_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TimingOfTransferOfGoodOrServiceDomain_dad33429-acec-4602-ab46-a05fec1b2e39" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TimingOfTransferOfGoodOrServiceDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_TimingOfTransferOfGoodOrServiceAxis_9648d05e-54d4-4aa0-a4a3-21be6bae3f81" xlink:to="loc_us-gaap_TimingOfTransferOfGoodOrServiceDomain_dad33429-acec-4602-ab46-a05fec1b2e39" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransferredAtPointInTimeMember_1c7cfdea-abc8-458f-a8f1-de8bcfdaf9e3" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TransferredAtPointInTimeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TimingOfTransferOfGoodOrServiceDomain_dad33429-acec-4602-ab46-a05fec1b2e39" xlink:to="loc_us-gaap_TransferredAtPointInTimeMember_1c7cfdea-abc8-458f-a8f1-de8bcfdaf9e3" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TransferredOverTimeMember_ec06e96b-cab7-4fbb-861a-f1b825c7a191" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_TransferredOverTimeMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_TimingOfTransferOfGoodOrServiceDomain_dad33429-acec-4602-ab46-a05fec1b2e39" xlink:to="loc_us-gaap_TransferredOverTimeMember_ec06e96b-cab7-4fbb-861a-f1b825c7a191" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_e9b0f20e-b1e3-417f-8be5-15afce40f9fe" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_StatementBusinessSegmentsAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_DisaggregationOfRevenueTable_c31b3bac-7a5f-48d8-b2f2-04544fc19178" xlink:to="loc_us-gaap_StatementBusinessSegmentsAxis_e9b0f20e-b1e3-417f-8be5-15afce40f9fe" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_e9b0f20e-b1e3-417f-8be5-15afce40f9fe_default" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_e9b0f20e-b1e3-417f-8be5-15afce40f9fe" xlink:to="loc_us-gaap_SegmentDomain_e9b0f20e-b1e3-417f-8be5-15afce40f9fe_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain_5570c403-8b06-4b24-993b-b639a1a74227" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_SegmentDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_e9b0f20e-b1e3-417f-8be5-15afce40f9fe" xlink:to="loc_us-gaap_SegmentDomain_5570c403-8b06-4b24-993b-b639a1a74227" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_RenewablesMember_95230315-299e-4eef-816b-a884a28b8355" xlink:href="rock-20231231.xsd#rock_RenewablesMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_5570c403-8b06-4b24-993b-b639a1a74227" xlink:to="loc_rock_RenewablesMember_95230315-299e-4eef-816b-a884a28b8355" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_ResidentialMember_02f04258-bba7-4cc6-a3a0-2d7392560f5b" xlink:href="rock-20231231.xsd#rock_ResidentialMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_5570c403-8b06-4b24-993b-b639a1a74227" xlink:to="loc_rock_ResidentialMember_02f04258-bba7-4cc6-a3a0-2d7392560f5b" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_AgtechMember_90c40635-8745-474c-9ad2-7dd6bf925bd0" xlink:href="rock-20231231.xsd#rock_AgtechMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_5570c403-8b06-4b24-993b-b639a1a74227" xlink:to="loc_rock_AgtechMember_90c40635-8745-474c-9ad2-7dd6bf925bd0" xlink:type="arc" order="2"/>
    <link:loc xlink:type="locator" xlink:label="loc_rock_InfrastructureMember_0a1426d8-2542-4187-91a2-66e7896431e5" xlink:href="rock-20231231.xsd#rock_InfrastructureMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_SegmentDomain_5570c403-8b06-4b24-993b-b639a1a74227" xlink:to="loc_rock_InfrastructureMember_0a1426d8-2542-4187-91a2-66e7896431e5" xlink:type="arc" order="3"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Revenues_3118be5e-8fb5-4a25-8fc3-7cf64dcaf53b" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_Revenues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_DisaggregationOfRevenueLineItems_361b969e-d7c8-47b5-a5be-75ff020060e2" xlink:to="loc_us-gaap_Revenues_3118be5e-8fb5-4a25-8fc3-7cf64dcaf53b" xlink:type="arc" order="0"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://www.gibraltar1.com/role/SegmentInformationNetSalesbyRegionorOriginandLongLivedAssetsbyRegionofDomicileDetails" xlink:type="simple" xlink:href="rock-20231231.xsd#SegmentInformationNetSalesbyRegionorOriginandLongLivedAssetsbyRegionofDomicileDetails"/>
  <link:definitionLink xlink:role="http://www.gibraltar1.com/role/SegmentInformationNetSalesbyRegionorOriginandLongLivedAssetsbyRegionofDomicileDetails" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenuesFromExternalCustomersAndLongLivedAssetsLineItems_7bc2a35e-828c-414c-8c2d-f926ac3faef9" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_RevenuesFromExternalCustomersAndLongLivedAssetsLineItems"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsTable_110fa7cf-b9d6-4526-8d31-743dbf77847e" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsTable"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/all" xlink:from="loc_us-gaap_RevenuesFromExternalCustomersAndLongLivedAssetsLineItems_7bc2a35e-828c-414c-8c2d-f926ac3faef9" xlink:to="loc_us-gaap_ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsTable_110fa7cf-b9d6-4526-8d31-743dbf77847e" xlink:type="arc" order="1" xbrldt:closed="true" xbrldt:contextElement="segment"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_StatementGeographicalAxis_ff0d9a13-2ccb-4773-97fa-7088a7620a76" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_StatementGeographicalAxis"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/hypercube-dimension" xlink:from="loc_us-gaap_ScheduleOfRevenuesFromExternalCustomersAndLongLivedAssetsTable_110fa7cf-b9d6-4526-8d31-743dbf77847e" xlink:to="loc_srt_StatementGeographicalAxis_ff0d9a13-2ccb-4773-97fa-7088a7620a76" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_ff0d9a13-2ccb-4773-97fa-7088a7620a76_default" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-default" xlink:from="loc_srt_StatementGeographicalAxis_ff0d9a13-2ccb-4773-97fa-7088a7620a76" xlink:to="loc_srt_SegmentGeographicalDomain_ff0d9a13-2ccb-4773-97fa-7088a7620a76_default" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SegmentGeographicalDomain_a524d041-0e9e-4f0b-ac5a-d7a0dcce8c66" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_SegmentGeographicalDomain"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/dimension-domain" xlink:from="loc_srt_StatementGeographicalAxis_ff0d9a13-2ccb-4773-97fa-7088a7620a76" xlink:to="loc_srt_SegmentGeographicalDomain_a524d041-0e9e-4f0b-ac5a-d7a0dcce8c66" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_NorthAmericaMember_5ec072b6-094e-420b-a824-06f6d4f6d69f" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_NorthAmericaMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_a524d041-0e9e-4f0b-ac5a-d7a0dcce8c66" xlink:to="loc_srt_NorthAmericaMember_5ec072b6-094e-420b-a824-06f6d4f6d69f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_srt_AsiaMember_b521fbc3-6f4a-4712-a518-ca5d4309d2d4" xlink:href="https://xbrl.fasb.org/srt/2023/elts/srt-2023.xsd#srt_AsiaMember"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_srt_SegmentGeographicalDomain_a524d041-0e9e-4f0b-ac5a-d7a0dcce8c66" xlink:to="loc_srt_AsiaMember_b521fbc3-6f4a-4712-a518-ca5d4309d2d4" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Revenues_ee65ef59-f397-4016-b8aa-e02c8cfcb13f" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_Revenues"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenuesFromExternalCustomersAndLongLivedAssetsLineItems_7bc2a35e-828c-414c-8c2d-f926ac3faef9" xlink:to="loc_us-gaap_Revenues_ee65ef59-f397-4016-b8aa-e02c8cfcb13f" xlink:type="arc" order="0"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NoncurrentAssets_1d5b9f31-99a6-4c6d-9d30-7c95bd667532" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_NoncurrentAssets"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_RevenuesFromExternalCustomersAndLongLivedAssetsLineItems_7bc2a35e-828c-414c-8c2d-f926ac3faef9" xlink:to="loc_us-gaap_NoncurrentAssets_1d5b9f31-99a6-4c6d-9d30-7c95bd667532" xlink:type="arc" order="1"/>
  </link:definitionLink>
  <link:roleRef roleURI="http://fasb.org/us-gaap/role/eedm/ExtensibleEnumerationLists" xlink:type="simple" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-roles-2023.xsd#eedm"/>
  <link:definitionLink xlink:role="http://fasb.org/us-gaap/role/eedm/ExtensibleEnumerationLists" xlink:type="extended">
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_IncomeStatementAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillAndIntangibleAssetImpairment" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_GoodwillAndIntangibleAssetImpairment"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_IncomeStatementAbstract" xlink:to="loc_us-gaap_GoodwillAndIntangibleAssetImpairment" xlink:type="arc" order="1"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesCurrentAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_LiabilitiesCurrentAbstract"/>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccruedLiabilitiesCurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2023/elts/us-gaap-2023.xsd#us-gaap_AccruedLiabilitiesCurrent"/>
    <link:definitionArc xlink:arcrole="http://xbrl.org/int/dim/arcrole/domain-member" xlink:from="loc_us-gaap_LiabilitiesCurrentAbstract" xlink:to="loc_us-gaap_AccruedLiabilitiesCurrent" xlink:type="arc" order="1"/>
  </link:definitionLink>
</link:linkbase>
