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  <xs:element id="ajg_FacilityCAndFacilityDMember" abstract="true" name="FacilityCAndFacilityDMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="ajg_DebtLongTermAndShortTermCombinedAmountGross" abstract="false" name="DebtLongTermAndShortTermCombinedAmountGross" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="ajg_DebtInstrumentNumberOfTranches" abstract="false" name="DebtInstrumentNumberOfTranches" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:integerItemType"/>
  <xs:element id="ajg_SeriesONoteMember" abstract="true" name="SeriesONoteMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="ajg_SeriesHHNoteMember" abstract="true" name="SeriesHHNoteMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="ajg_SeriesHNoteMember" abstract="true" name="SeriesHNoteMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="ajg_OperatingCashToFund" abstract="false" name="OperatingCashToFund" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="ajg_AmountPayableToRedeemNotesPercentOfPrincipalAmount" abstract="false" name="AmountPayableToRedeemNotesPercentOfPrincipalAmount" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="ajg_UnsecuredMulticurrencyCreditAgreementMember" abstract="true" name="UnsecuredMulticurrencyCreditAgreementMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="ajg_SwinglineSubFacilityMember" abstract="true" name="SwinglineSubFacilityMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="ajg_FixedRateOverReferenceRates" abstract="false" name="FixedRateOverReferenceRates" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="ajg_AnnualFacilityFeeOfRevolvingCreditFacility" abstract="false" name="AnnualFacilityFeeOfRevolvingCreditFacility" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="ajg_FacilityCMember" abstract="true" name="FacilityCMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="ajg_FacilityDMember" abstract="true" name="FacilityDMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="ajg_DebtInstrumentNumberOfFacilities" abstract="false" name="DebtInstrumentNumberOfFacilities" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:integerItemType"/>
  <xs:element id="ajg_WeightedAverageNumberOfCommonAndCommonEquivalentSharesOutstanding" abstract="false" name="WeightedAverageNumberOfCommonAndCommonEquivalentSharesOutstanding" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:sharesItemType"/>
  <xs:element id="ajg_AnnualActivityOfStockOptionPlansTable" abstract="true" name="AnnualActivityOfStockOptionPlansTable" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType"/>
  <xs:element id="ajg_LongTermIncentivePlanMember" abstract="true" name="LongTermIncentivePlanMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="ajg_TwoThousandSeventeenLongTermincentivePlanMember" abstract="true" name="TwoThousandSeventeenLongTermincentivePlanMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="ajg_BlackScholesOptionPricingModelMember" abstract="true" name="BlackScholesOptionPricingModelMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="ajg_FullValueAwardsInExcessOfTheLimitMember" abstract="true" name="FullValueAwardsInExcessOfTheLimitMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="ajg_FullValueAwardsUpToTheLimitMember" abstract="true" name="FullValueAwardsUpToTheLimitMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="ajg_FullValueAwardsMember" abstract="true" name="FullValueAwardsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="ajg_StockOptionPlansLineItems" abstract="true" name="StockOptionPlansLineItems" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="ajg_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsSharePool" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsSharePool" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:sharesItemType"/>
  <xs:element id="ajg_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsSharesAgainstPool" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsSharesAgainstPool" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:sharesItemType"/>
  <xs:element id="ajg_NumberOfPeriodsOptionsExpire" abstract="false" name="NumberOfPeriodsOptionsExpire" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="ajg_ExercisePriceOfStockOptionsPercentOfFairMarketValueOfShareOfCommonStockOnDateOfGrant" abstract="false" name="ExercisePriceOfStockOptionsPercentOfFairMarketValueOfShareOfCommonStockOnDateOfGrant" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="ajg_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodExercisePercentageYearOne" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodExercisePercentageYearOne" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="ajg_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodExercisePercentageYearTwo" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodExercisePercentageYearTwo" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="ajg_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodExercisePercentageYearThree" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodExercisePercentageYearThree" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="ajg_PeriodForOptionsToExpireFromDateOfGrant" abstract="false" name="PeriodForOptionsToExpireFromDateOfGrant" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="ajg_AgeOfEmployeeNoLongerSubjectToAwardForfeitureOnConditionCompliance" abstract="false" name="AgeOfEmployeeNoLongerSubjectToAwardForfeitureOnConditionCompliance" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="ajg_PeriodOfServiceFromGrantDateStockOptionsAwardedNotSubjectToForfeiture" abstract="false" name="PeriodOfServiceFromGrantDateStockOptionsAwardedNotSubjectToForfeiture" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="ajg_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisedInPeriodIntrinsicValue" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisedInPeriodIntrinsicValue" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="ajg_WeightedAveragePeriod" abstract="false" name="WeightedAveragePeriod" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="ajg_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsNonVestedAndExpectedToVestNumberOfShares" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsNonVestedAndExpectedToVestNumberOfShares" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:sharesItemType"/>
  <xs:element id="ajg_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsNonvestedAndExpectedToVestExercisableWeightedAverageExercisePrice" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsNonvestedAndExpectedToVestExercisableWeightedAverageExercisePrice" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types:perShareItemType"/>
  <xs:element id="ajg_SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedAndExpectedToVestOutstandingWeightedAverageRemainingContractualTerm" abstract="false" name="SharebasedCompensationArrangementBySharebasedPaymentAwardOptionsNonvestedAndExpectedToVestOutstandingWeightedAverageRemainingContractualTerm" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="ajg_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingAggregateIntrinsicValue" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingAggregateIntrinsicValue" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="ajg_SharebasedCompensationArrangementNonVestedAndExpectedToVestOutstandingAggregateIntrinsicValue" abstract="false" name="SharebasedCompensationArrangementNonVestedAndExpectedToVestOutstandingAggregateIntrinsicValue" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="ajg_Range01Member" abstract="true" name="Range01Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="ajg_Range02Member" abstract="true" name="Range02Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="ajg_Range03Member" abstract="true" name="Range03Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="ajg_Range04Member" abstract="true" name="Range04Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="ajg_Range05Member" abstract="true" name="Range05Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="ajg_Range06Member" abstract="true" name="Range06Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="ajg_Range07Member" abstract="true" name="Range07Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="ajg_Range08Member" abstract="true" name="Range08Member" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="ajg_InvestmentsAndEmployeeDeferredCompensationPlanTable" abstract="true" name="InvestmentsAndEmployeeDeferredCompensationPlanTable" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType"/>
  <xs:element id="ajg_DeferredEquityParticipationPlanMember" abstract="true" name="DeferredEquityParticipationPlanMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="ajg_DeferredEquityParticipationPlanSubPlansMember" abstract="true" name="DeferredEquityParticipationPlanSubPlansMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="ajg_DeferredCashParticipationPlanMember" abstract="true" name="DeferredCashParticipationPlanMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="ajg_InvestmentsAndEmployeeDeferredCompensationPlanLineItems" abstract="true" name="InvestmentsAndEmployeeDeferredCompensationPlanLineItems" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="ajg_CompensationApprovedByCommitteeValue" abstract="false" name="CompensationApprovedByCommitteeValue" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="ajg_ProceedsFromSubPlan" abstract="false" name="ProceedsFromSubPlan" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="ajg_UnearnedDeferredCompensationValue" abstract="false" name="UnearnedDeferredCompensationValue" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="ajg_UnearnedDeferredCompensationShare" abstract="false" name="UnearnedDeferredCompensationShare" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:sharesItemType"/>
  <xs:element id="ajg_CashAndEquityAwardWithAggregateFairValueVestedAndDistributedToParticipants" abstract="false" name="CashAndEquityAwardWithAggregateFairValueVestedAndDistributedToParticipants" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="ajg_CommonStockOptionsRestrictedStockWarrantsAndChangesInCapitalizationTable" abstract="true" name="CommonStockOptionsRestrictedStockWarrantsAndChangesInCapitalizationTable" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType"/>
  <xs:element id="ajg_RestrictedStockRestrictedStockUnitsAndPerformanceUnitAwardsMember" abstract="true" name="RestrictedStockRestrictedStockUnitsAndPerformanceUnitAwardsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="ajg_UnvestedRestrictedStockMember" abstract="true" name="UnvestedRestrictedStockMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="ajg_CashAwardsMember" abstract="true" name="CashAwardsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="ajg_TwoThousandTwentyTwoProvisionalCashAwardsMember" abstract="true" name="TwoThousandTwentyTwoProvisionalCashAwardsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="ajg_TwoThousandTwentyOneProvisionalCashAwardsMember" abstract="true" name="TwoThousandTwentyOneProvisionalCashAwardsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="ajg_TwoThousandTwentyProvisionalCashAwardsMember" abstract="true" name="TwoThousandTwentyProvisionalCashAwardsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="ajg_EmployeeEmployedByAssuredPartnersMember" abstract="true" name="EmployeeEmployedByAssuredPartnersMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="ajg_FormerAssuredPartnersEmployeeEmployedWithGallagherMember" abstract="true" name="FormerAssuredPartnersEmployeeEmployedWithGallagherMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="ajg_CommonStockOptionsRestrictedStockWarrantsAndChangesInCapitalizationLineItems" abstract="true" name="CommonStockOptionsRestrictedStockWarrantsAndChangesInCapitalizationLineItems" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="ajg_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodFairValue" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriodFairValue" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="ajg_ShareBasedCompensationArrangementByShareBasedPaymentAwardAggregateFairValue" abstract="false" name="ShareBasedCompensationArrangementByShareBasedPaymentAwardAggregateFairValue" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="ajg_ShareBasedCompensationArrangementConversionRatioToCommonStock" abstract="false" name="ShareBasedCompensationArrangementConversionRatioToCommonStock" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:pureItemType"/>
  <xs:element id="ajg_UltimateAwardValueMultiplesOfOriginalValueOfUnitsMinimum" abstract="false" name="UltimateAwardValueMultiplesOfOriginalValueOfUnitsMinimum" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:decimalItemType"/>
  <xs:element id="ajg_UltimateAwardValueMultiplesOfOriginalValueOfUnitsMaximum" abstract="false" name="UltimateAwardValueMultiplesOfOriginalValueOfUnitsMaximum" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:decimalItemType"/>
  <xs:element id="ajg_ProvisionalCompensationCashAwardApprovedForFutureGrantByCompensationCommitteeValue" abstract="false" name="ProvisionalCompensationCashAwardApprovedForFutureGrantByCompensationCommitteeValue" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="ajg_ProvisionalCompensationCashAwardApprovedForFutureGrantByCompensationCommitteeUnits" abstract="false" name="ProvisionalCompensationCashAwardApprovedForFutureGrantByCompensationCommitteeUnits" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:sharesItemType"/>
  <xs:element id="ajg_CashBasedCompensationAwardExpenses" abstract="false" name="CashBasedCompensationAwardExpenses" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="ajg_ProvisionalCompensationCashAwardWithAggregateFairValueVestedAndDistributedToParticipants" abstract="false" name="ProvisionalCompensationCashAwardWithAggregateFairValueVestedAndDistributedToParticipants" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="ajg_VestingPeriodTable" abstract="true" name="VestingPeriodTable" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType"/>
  <xs:element id="ajg_VestingPeriodOneYearMember" abstract="true" name="VestingPeriodOneYearMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="ajg_VestingPeriodFiveYearsMember" abstract="true" name="VestingPeriodFiveYearsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="ajg_VestingPeriodLineItems" abstract="true" name="VestingPeriodLineItems" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="ajg_QualifiedContributorySavingsAndThriftFourZeroOneKPlanMember" abstract="true" name="QualifiedContributorySavingsAndThriftFourZeroOneKPlanMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="ajg_NonQualifiedDeferredCompensationPlanMember" abstract="true" name="NonQualifiedDeferredCompensationPlanMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="ajg_RetirementBenefitsRequiredEmploymentPeriod" abstract="false" name="RetirementBenefitsRequiredEmploymentPeriod" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="ajg_NumberOfFrozenDefinedBenefitPensionPlans" abstract="false" name="NumberOfFrozenDefinedBenefitPensionPlans" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:integerItemType"/>
  <xs:element id="ajg_DefinedBenefitPensionPlanReversalOfDeferredTaxAsset" abstract="false" name="DefinedBenefitPensionPlanReversalOfDeferredTaxAsset" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="ajg_ExpectedPeriodOfReturnOnPlanAssets" abstract="false" name="ExpectedPeriodOfReturnOnPlanAssets" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="ajg_DefinedBenefitPlanPercentageOfEligibleCompensationForMatchingContributionsByEmployer" abstract="false" name="DefinedBenefitPlanPercentageOfEligibleCompensationForMatchingContributionsByEmployer" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="ajg_MatchingContributionsVestingSchedule" abstract="false" name="MatchingContributionsVestingSchedule" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:durationItemType"/>
  <xs:element id="ajg_DefinedBenefitPlanAdditionalPercentageOfEligibleCompensationForMatchingContributionsByEmployer" abstract="false" name="DefinedBenefitPlanAdditionalPercentageOfEligibleCompensationForMatchingContributionsByEmployer" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="ajg_DefinedBenefitPlanPlanAssetsNumberOfUnderwritingEnterprises" abstract="false" name="DefinedBenefitPlanPlanAssetsNumberOfUnderwritingEnterprises" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:integerItemType"/>
  <xs:element id="ajg_DefinedBenefitPlanNetAmountIncludedInRetainedEarning" abstract="false" name="DefinedBenefitPlanNetAmountIncludedInRetainedEarning" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="ajg_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationExpectedLongTermReturnOnPlanAssets" abstract="false" name="DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationExpectedLongTermReturnOnPlanAssets" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="ajg_DefinedBenefitPlansUnrealizedGainsLosses" abstract="false" name="DefinedBenefitPlansUnrealizedGainsLosses" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="ajg_CashPaidForAmountsIncludedInMeasurementOfLeaseLiabilitiesAbstract" abstract="true" name="CashPaidForAmountsIncludedInMeasurementOfLeaseLiabilitiesAbstract" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="ajg_AccruedCompensationAndOtherCurrentLiabilitiesMember" abstract="true" name="AccruedCompensationAndOtherCurrentLiabilitiesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="ajg_CommissionRevenueMember" abstract="true" name="CommissionRevenueMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="ajg_LaborAndRelatedExpenseMember" abstract="true" name="LaborAndRelatedExpenseMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="ajg_AmountOfGainLossRecognizedEffectivenessTesting" abstract="false" name="AmountOfGainLossRecognizedEffectivenessTesting" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="ajg_CommitmentsContingenciesAndOffBalanceSheetArrangementsTable" abstract="true" name="CommitmentsContingenciesAndOffBalanceSheetArrangementsTable" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType"/>
  <xs:element id="ajg_CreditAgreementMember" abstract="true" name="CreditAgreementMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="ajg_InterestOnDebtMember" abstract="true" name="InterestOnDebtMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="ajg_DebtObligationMember" abstract="true" name="DebtObligationMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="ajg_OperatingLeaseObligationMember" abstract="true" name="OperatingLeaseObligationMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="ajg_SubleaseArrangementsMember" abstract="true" name="SubleaseArrangementsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="ajg_OutstandingPurchaseObligationsMember" abstract="true" name="OutstandingPurchaseObligationsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="ajg_ContractualObligationsMember" abstract="true" name="ContractualObligationsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="ajg_CommitmentsContingenciesAndOffBalanceSheetArrangementsLineItems" abstract="true" name="CommitmentsContingenciesAndOffBalanceSheetArrangementsLineItems" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="ajg_RecordedUnconditionalPurchaseObligationReceivableWithinOneYear" abstract="false" name="RecordedUnconditionalPurchaseObligationReceivableWithinOneYear" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="ajg_RecordedUnconditionalPurchaseObligationReceivableInSecondYear" abstract="false" name="RecordedUnconditionalPurchaseObligationReceivableInSecondYear" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="ajg_RecordedUnconditionalPurchaseObligationReceivableInThirdYear" abstract="false" name="RecordedUnconditionalPurchaseObligationReceivableInThirdYear" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="ajg_RecordedUnconditionalPurchaseObligationReceivableInFourthYear" abstract="false" name="RecordedUnconditionalPurchaseObligationReceivableInFourthYear" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="ajg_RecordedUnconditionalPurchaseObligationReceivableInFifthYear" abstract="false" name="RecordedUnconditionalPurchaseObligationReceivableInFifthYear" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="ajg_RecordedUnconditionalPurchaseObligationReceivableAfterYearFive" abstract="false" name="RecordedUnconditionalPurchaseObligationReceivableAfterYearFive" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="ajg_RecordedUnconditionalPurchaseObligationReceivable" abstract="false" name="RecordedUnconditionalPurchaseObligationReceivable" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="ajg_TaxIncrementFinancingMember" abstract="true" name="TaxIncrementFinancingMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="ajg_UnconsolidatedInvestmentsInEnterprisesMember" abstract="true" name="UnconsolidatedInvestmentsInEnterprisesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="ajg_SelfInsuranceDeductiblesMember" abstract="true" name="SelfInsuranceDeductiblesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="ajg_RentCaptiveFacilityMember" abstract="true" name="RentCaptiveFacilityMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="ajg_ErrorsAndOmissionsMember" abstract="true" name="ErrorsAndOmissionsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="ajg_SecurityDepositMember" abstract="true" name="SecurityDepositMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="ajg_UpToFifteenMillionMember" abstract="true" name="UpToFifteenMillionMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="ajg_UpToTwoMillionMember" abstract="true" name="UpToTwoMillionMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="ajg_UpToTenMillionMember" abstract="true" name="UpToTenMillionMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="ajg_UpToTwentyMillionMember" abstract="true" name="UpToTwentyMillionMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="ajg_NumberOfSquareFeet" abstract="false" name="NumberOfSquareFeet" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="dtr-types:areaItemType"/>
  <xs:element id="ajg_EconomicDevelopmentForGrowingEconomyTaxCredit" abstract="false" name="EconomicDevelopmentForGrowingEconomyTaxCredit" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="ajg_NumberOfLetterOfCreditIssued" abstract="false" name="NumberOfLetterOfCreditIssued" nillable="true" xbrli:periodType="instant" substitutionGroup="xbrli:item" type="xbrli:integerItemType"/>
  <xs:element id="ajg_LiabilitiesRecordedOnSelfInsurance" abstract="false" name="LiabilitiesRecordedOnSelfInsurance" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="ajg_LettersOfCreditMember" abstract="true" name="LettersOfCreditMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="ajg_AmountOfCommitmentExpirationOffBalanceSheetCommitmentsWithinYearOne" abstract="false" name="AmountOfCommitmentExpirationOffBalanceSheetCommitmentsWithinYearOne" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="ajg_AmountOfCommitmentExpirationOffBalanceSheetCommitmentsWithinYearTwo" abstract="false" name="AmountOfCommitmentExpirationOffBalanceSheetCommitmentsWithinYearTwo" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="ajg_AmountOfCommitmentExpirationOffBalanceSheetCommitmentsWithinYearThree" abstract="false" name="AmountOfCommitmentExpirationOffBalanceSheetCommitmentsWithinYearThree" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="ajg_AmountOfCommitmentExpirationOffBalanceSheetCommitmentsWithinYearFour" abstract="false" name="AmountOfCommitmentExpirationOffBalanceSheetCommitmentsWithinYearFour" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="ajg_AmountOfCommitmentExpirationOffBalanceSheetCommitmentsWithinYearFive" abstract="false" name="AmountOfCommitmentExpirationOffBalanceSheetCommitmentsWithinYearFive" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="ajg_AmountOfCommitmentExpirationOffBalanceSheetCommitmentsWithinYearThereafter" abstract="false" name="AmountOfCommitmentExpirationOffBalanceSheetCommitmentsWithinYearThereafter" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="ajg_AmountOfCommitmentExpirationOffBalanceSheetCommitments" abstract="false" name="AmountOfCommitmentExpirationOffBalanceSheetCommitments" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="ajg_CreditSupportUnderLettersOfCreditForDeductiblesDueByUsOnOurOwnInsuranceCoveragesExpiresAfterTwoThousandAndTwentyEightMember" abstract="true" name="CreditSupportUnderLettersOfCreditForDeductiblesDueByUsOnOurOwnInsuranceCoveragesExpiresAfterTwoThousandAndTwentyEightMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="ajg_CreditEnhancementUnderLettersOfCreditForOurCaptiveInsuranceOperationsToMeetMinimumStatutoryCapitalRequirementsExpiresAfterTwoThousandAndTwentyEightMember" abstract="true" name="CreditEnhancementUnderLettersOfCreditForOurCaptiveInsuranceOperationsToMeetMinimumStatutoryCapitalRequirementsExpiresAfterTwoThousandAndTwentyEightMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="ajg_CollateralRelatedToClaimFundsHeldInAFiduciaryCapacityByARecentAcquisitionExpiresTwoThousandTwentyEightMember" abstract="true" name="CollateralRelatedToClaimFundsHeldInAFiduciaryCapacityByARecentAcquisitionExpiresTwoThousandTwentyEightMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="ajg_OffBalanceSheetLiabilityMaximumExposure" abstract="false" name="OffBalanceSheetLiabilityMaximumExposure" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="ajg_IncomeTaxExpenseBenefitTable" abstract="true" name="IncomeTaxExpenseBenefitTable" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrldt:hypercubeItem" type="xbrli:stringItemType"/>
  <xs:element id="ajg_IncomeTaxExpenseBenefitLineItems" abstract="true" name="IncomeTaxExpenseBenefitLineItems" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="xbrli:stringItemType"/>
  <xs:element id="ajg_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseExecutiveCompensationAmount" abstract="false" name="EffectiveIncomeTaxRateReconciliationNondeductibleExpenseExecutiveCompensationAmount" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="ajg_EffectiveIncomeTaxRateReconciliationBranchesAndDisregardedEntitiesAmount" abstract="false" name="EffectiveIncomeTaxRateReconciliationBranchesAndDisregardedEntitiesAmount" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="ajg_EffectiveIncomeTaxRateReconciliationEarnoutLiabilityAdjustmentsAmount" abstract="false" name="EffectiveIncomeTaxRateReconciliationEarnoutLiabilityAdjustmentsAmount" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="ajg_EffectiveIncomeTaxRateReconciliationNondeductibleExpenseExecutiveCompensationPercent" abstract="false" name="EffectiveIncomeTaxRateReconciliationNondeductibleExpenseExecutiveCompensationPercent" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="ajg_EffectiveIncomeTaxRateReconciliationBranchesAndDisregardedEntitiesPercent" abstract="false" name="EffectiveIncomeTaxRateReconciliationBranchesAndDisregardedEntitiesPercent" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="ajg_EffectiveIncomeTaxRateReconciliationEarnoutLiabilityAdjustmentsPercent" abstract="false" name="EffectiveIncomeTaxRateReconciliationEarnoutLiabilityAdjustmentsPercent" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="ajg_EffectiveIncomeTaxRateReconciliationForeignTaxCreditFromBranchesAndDisregardedEntitiesAmount" abstract="false" name="EffectiveIncomeTaxRateReconciliationForeignTaxCreditFromBranchesAndDisregardedEntitiesAmount" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="ajg_IncomeTaxReconciliationOtherPermanentDifferences" abstract="false" name="IncomeTaxReconciliationOtherPermanentDifferences" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="ajg_IncomeTaxReconciliationChangesInUnrecognizedTaxBenefitsRelatedToResolutionOfFederalAndStateAuditsExpirationOfVariousStatutesOfLimitationsAndOtherItems" abstract="false" name="IncomeTaxReconciliationChangesInUnrecognizedTaxBenefitsRelatedToResolutionOfFederalAndStateAuditsExpirationOfVariousStatutesOfLimitationsAndOtherItems" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="ajg_EffectiveIncomeTaxRateReconciliationOtherPermanentDifferences" abstract="false" name="EffectiveIncomeTaxRateReconciliationOtherPermanentDifferences" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="ajg_EffectiveIncomeTaxRateReconciliationChangesInUnrecognizedTaxBenefitsRelatedToResolutionOfFederalAndStateAuditsExpirationOfVariousStatutesOfLimitationsAndOtherItems" abstract="false" name="EffectiveIncomeTaxRateReconciliationChangesInUnrecognizedTaxBenefitsRelatedToResolutionOfFederalAndStateAuditsExpirationOfVariousStatutesOfLimitationsAndOtherItems" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:percentItemType"/>
  <xs:element id="ajg_NoncurrentLiabilitiesMember" abstract="true" name="NoncurrentLiabilitiesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="ajg_GeneralBusinessAndOtherMember" abstract="true" name="GeneralBusinessAndOtherMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="ajg_DeferredTaxAssetsAccruedAndUnfundedCompensationAndEmployeeBenefits" abstract="false" name="DeferredTaxAssetsAccruedAndUnfundedCompensationAndEmployeeBenefits" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="ajg_DeferredTaxAssetsLeaseLiabilities" abstract="false" name="DeferredTaxAssetsLeaseLiabilities" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="ajg_DeferredTaxAssetsRevenueRecognition" abstract="false" name="DeferredTaxAssetsRevenueRecognition" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="ajg_DeferredTaxLiabilitiesAccruedPensionLiability" abstract="false" name="DeferredTaxLiabilitiesAccruedPensionLiability" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="ajg_DeferredTaxLiabilitiesRightOfUseAsset" abstract="false" name="DeferredTaxLiabilitiesRightOfUseAsset" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="ajg_DeferredTaxLiabilitiesHedgingInstruments" abstract="false" name="DeferredTaxLiabilitiesHedgingInstruments" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="ajg_DeferredTaxLiabilitiesOtherPrepaidItems" abstract="false" name="DeferredTaxLiabilitiesOtherPrepaidItems" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="ajg_DeferredTaxLiabilitiesRevenueRecognition" abstract="false" name="DeferredTaxLiabilitiesRevenueRecognition" nillable="true" xbrli:periodType="instant" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="ajg_CashAndCashEquivalentsRestrictedCashAndFiduciaryCash" abstract="false" name="CashAndCashEquivalentsRestrictedCashAndFiduciaryCash" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="ajg_IncreaseDecreaseInInvestmentIncomeDividend" abstract="false" name="IncreaseDecreaseInInvestmentIncomeDividend" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="ajg_ProceedsFromAssuredPartnersFinancing" abstract="false" name="ProceedsFromAssuredPartnersFinancing" nillable="true" xbrli:periodType="duration" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="ajg_CashAndCashEquivalentsExcludingRestrictedCash" abstract="false" name="CashAndCashEquivalentsExcludingRestrictedCash" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="ajg_CashCashEquivalentsRestrictedCashAndFiduciaryCash" abstract="false" name="CashCashEquivalentsRestrictedCashAndFiduciaryCash" nillable="true" xbrli:periodType="instant" xbrli:balance="debit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
  <xs:element id="ajg_AllowanceForEstimatedPolicyCancellationsMember" abstract="true" name="AllowanceForEstimatedPolicyCancellationsMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="ajg_AccumulatedAmortizationOfExpirationListsNonCompeteAgreementsAndTradeNamesMember" abstract="true" name="AccumulatedAmortizationOfExpirationListsNonCompeteAgreementsAndTradeNamesMember" nillable="true" xbrli:periodType="duration" substitutionGroup="xbrli:item" type="dtr-types:domainItemType"/>
  <xs:element id="ajg_ValuationAllowancesAndReservesAdditionsChargedToEarnings" abstract="false" name="ValuationAllowancesAndReservesAdditionsChargedToEarnings" nillable="true" xbrli:periodType="duration" xbrli:balance="credit" substitutionGroup="xbrli:item" type="xbrli:monetaryItemType"/>
</xs:schema>
