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<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" xsi:schemaLocation="http://www.xbrl.org/2003/linkbase http://www.xbrl.org/2003/xbrl-linkbase-2003-12-31.xsd">
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  <link:labelLink xlink:role="http://www.xbrl.org/2003/role/link" xlink:type="extended">
    <link:label id="lab_sigi_DividendEquivalentUnitsMember_fee12a59-8dd9-4c46-b052-7e6dc32464c9_terseLabel_en-US" xlink:label="lab_sigi_DividendEquivalentUnitsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Dividend Equivalent Units [Member]</link:label>
    <link:label id="lab_sigi_DividendEquivalentUnitsMember_label_en-US" xlink:label="lab_sigi_DividendEquivalentUnitsMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Dividend Equivalent Units [Member]</link:label>
    <link:label id="lab_sigi_DividendEquivalentUnitsMember_documentation_en-US" xlink:label="lab_sigi_DividendEquivalentUnitsMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Dividend Equivalent Units represent equivalent units earned on restricted stock units that are reinvested in the Parent's common stock at fair value on each dividend payment date.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_DividendEquivalentUnitsMember" xlink:href="sigi-20211231.xsd#sigi_DividendEquivalentUnitsMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_DividendEquivalentUnitsMember" xlink:to="lab_sigi_DividendEquivalentUnitsMember" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_SevenPointTwentyFivePercentSeniorNotesMember_97287f33-c998-45b2-91f0-5639c4a25512_terseLabel_en-US" xlink:label="lab_sigi_SevenPointTwentyFivePercentSeniorNotesMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Seven Point Twenty Five Percent Senior Notes [Member]</link:label>
    <link:label id="lab_sigi_SevenPointTwentyFivePercentSeniorNotesMember_0342a96d-84c5-46fd-8d4b-88836c97c72a_verboseLabel_en-US" xlink:label="lab_sigi_SevenPointTwentyFivePercentSeniorNotesMember" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Seven Point Twenty Five Percent Senior Notes due 2034 [Member]</link:label>
    <link:label id="lab_sigi_SevenPointTwentyFivePercentSeniorNotesMember_label_en-US" xlink:label="lab_sigi_SevenPointTwentyFivePercentSeniorNotesMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Seven Point Twenty Five Percent Senior Notes [Member]</link:label>
    <link:label id="lab_sigi_SevenPointTwentyFivePercentSeniorNotesMember_documentation_en-US" xlink:label="lab_sigi_SevenPointTwentyFivePercentSeniorNotesMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">This item represents the 7.25% Senior Notes of the company due 2034.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_SevenPointTwentyFivePercentSeniorNotesMember" xlink:href="sigi-20211231.xsd#sigi_SevenPointTwentyFivePercentSeniorNotesMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_SevenPointTwentyFivePercentSeniorNotesMember" xlink:to="lab_sigi_SevenPointTwentyFivePercentSeniorNotesMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_SupplementalCashFlowInformationAbstract_6f80eda9-f0aa-4d35-b7ac-93d24f0264bc_terseLabel_en-US" xlink:label="lab_us-gaap_SupplementalCashFlowInformationAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Supplemental Cash Flow Information [Abstract]</link:label>
    <link:label id="lab_us-gaap_SupplementalCashFlowInformationAbstract_label_en-US" xlink:label="lab_us-gaap_SupplementalCashFlowInformationAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Supplemental Cash Flow Information [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SupplementalCashFlowInformationAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SupplementalCashFlowInformationAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SupplementalCashFlowInformationAbstract" xlink:to="lab_us-gaap_SupplementalCashFlowInformationAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpensePropertyCasualtyLiability_b241881f-cb03-49c6-b22c-319eaf036c61_terseLabel_en-US" xlink:label="lab_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpensePropertyCasualtyLiability" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Reserve for loss and loss expense (Note 10)</link:label>
    <link:label id="lab_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpensePropertyCasualtyLiability_f3b60232-7662-4a1a-88fc-828931b03c66_verboseLabel_en-US" xlink:label="lab_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpensePropertyCasualtyLiability" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Reserve for loss and loss expense</link:label>
    <link:label id="lab_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpensePropertyCasualtyLiability_label_en-US" xlink:label="lab_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpensePropertyCasualtyLiability" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Liability for Claims and Claims Adjustment Expense, Property Casualty Liability</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpensePropertyCasualtyLiability" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpensePropertyCasualtyLiability"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpensePropertyCasualtyLiability" xlink:to="lab_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpensePropertyCasualtyLiability" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AccumulatedNetUnrealizedInvestmentGainLossMember_1bf71c1f-042d-45ce-bc55-b41e63286b37_terseLabel_en-US" xlink:label="lab_us-gaap_AccumulatedNetUnrealizedInvestmentGainLossMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Accumulated Net Unrealized Investment Gain (Loss) [Member]</link:label>
    <link:label id="lab_us-gaap_AccumulatedNetUnrealizedInvestmentGainLossMember_label_en-US" xlink:label="lab_us-gaap_AccumulatedNetUnrealizedInvestmentGainLossMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">AOCI, Accumulated Gain (Loss), Debt Securities, Available-for-sale, Parent [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccumulatedNetUnrealizedInvestmentGainLossMember" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccumulatedNetUnrealizedInvestmentGainLossMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AccumulatedNetUnrealizedInvestmentGainLossMember" xlink:to="lab_us-gaap_AccumulatedNetUnrealizedInvestmentGainLossMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LegalMattersAndContingenciesTextBlock_4b0ece1e-c115-4d09-961d-7b71ed3b46c1_terseLabel_en-US" xlink:label="lab_us-gaap_LegalMattersAndContingenciesTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Litigation</link:label>
    <link:label id="lab_us-gaap_LegalMattersAndContingenciesTextBlock_label_en-US" xlink:label="lab_us-gaap_LegalMattersAndContingenciesTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Legal Matters and Contingencies [Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LegalMattersAndContingenciesTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LegalMattersAndContingenciesTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LegalMattersAndContingenciesTextBlock" xlink:to="lab_us-gaap_LegalMattersAndContingenciesTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DefinedBenefitPlanActuarialGainLoss_b42705e7-5e1f-49c9-9a99-27f51177f548_negatedLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanActuarialGainLoss" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Actuarial losses (gains)</link:label>
    <link:label id="lab_us-gaap_DefinedBenefitPlanActuarialGainLoss_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanActuarialGainLoss" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss)</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanActuarialGainLoss" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DefinedBenefitPlanActuarialGainLoss"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanActuarialGainLoss" xlink:to="lab_us-gaap_DefinedBenefitPlanActuarialGainLoss" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_b487c869-359b-457e-bcd5-b9b03515a285_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Vested in 2021, number of shares</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod" xlink:to="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_PrincipalAccelerationAmountStateofDefault_891190c0-433e-43a4-8890-dd1b76619495_terseLabel_en-US" xlink:label="lab_sigi_PrincipalAccelerationAmountStateofDefault" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Acceleration of principal</link:label>
    <link:label id="lab_sigi_PrincipalAccelerationAmountStateofDefault_label_en-US" xlink:label="lab_sigi_PrincipalAccelerationAmountStateofDefault" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Principal Acceleration Amount StateOf Default</link:label>
    <link:label id="lab_sigi_PrincipalAccelerationAmountStateofDefault_documentation_en-US" xlink:label="lab_sigi_PrincipalAccelerationAmountStateofDefault" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">This element represents the amount of concurrent debt outstanding which, if accelerated for any reason of default, causes an event of default on the referenced debt.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_PrincipalAccelerationAmountStateofDefault" xlink:href="sigi-20211231.xsd#sigi_PrincipalAccelerationAmountStateofDefault"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_PrincipalAccelerationAmountStateofDefault" xlink:to="lab_sigi_PrincipalAccelerationAmountStateofDefault" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_ConsolidatedEntitiesAxis_040aa8c6-215c-4c69-904b-726dc91cd675_terseLabel_en-US" xlink:label="lab_srt_ConsolidatedEntitiesAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Consolidated Entities [Axis]</link:label>
    <link:label id="lab_srt_ConsolidatedEntitiesAxis_label_en-US" xlink:label="lab_srt_ConsolidatedEntitiesAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Consolidated Entities [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesAxis" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ConsolidatedEntitiesAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_ConsolidatedEntitiesAxis" xlink:to="lab_srt_ConsolidatedEntitiesAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_EquityMethodInvestmentSummarizedFinancialInformationAssetsSIGI_0f68f6a8-233e-4211-8bb3-a132109f15dd_terseLabel_en-US" xlink:label="lab_sigi_EquityMethodInvestmentSummarizedFinancialInformationAssetsSIGI" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Assets</link:label>
    <link:label id="lab_sigi_EquityMethodInvestmentSummarizedFinancialInformationAssetsSIGI_label_en-US" xlink:label="lab_sigi_EquityMethodInvestmentSummarizedFinancialInformationAssetsSIGI" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Equity Method Investment Summarized Financial Information Assets SIGI</link:label>
    <link:label id="lab_sigi_EquityMethodInvestmentSummarizedFinancialInformationAssetsSIGI_documentation_en-US" xlink:label="lab_sigi_EquityMethodInvestmentSummarizedFinancialInformationAssetsSIGI" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">The amount of assets reported by an equity method investment of the entity.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_EquityMethodInvestmentSummarizedFinancialInformationAssetsSIGI" xlink:href="sigi-20211231.xsd#sigi_EquityMethodInvestmentSummarizedFinancialInformationAssetsSIGI"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_EquityMethodInvestmentSummarizedFinancialInformationAssetsSIGI" xlink:to="lab_sigi_EquityMethodInvestmentSummarizedFinancialInformationAssetsSIGI" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_PreferredStockSharesOutstanding_3cfdbf93-e0cd-4c2b-8223-911a68a1d48d_periodStartLabel_en-US" xlink:label="lab_us-gaap_PreferredStockSharesOutstanding" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Preferred stock, shares outstanding, beginning of period</link:label>
    <link:label id="lab_us-gaap_PreferredStockSharesOutstanding_e447831e-5208-4dbb-a5f0-b2514f327d38_periodEndLabel_en-US" xlink:label="lab_us-gaap_PreferredStockSharesOutstanding" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Preferred stock, shares outstanding, ending of period</link:label>
    <link:label id="lab_us-gaap_PreferredStockSharesOutstanding_label_en-US" xlink:label="lab_us-gaap_PreferredStockSharesOutstanding" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Preferred Stock, Shares Outstanding</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockSharesOutstanding" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PreferredStockSharesOutstanding"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PreferredStockSharesOutstanding" xlink:to="lab_us-gaap_PreferredStockSharesOutstanding" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_OtherIntangibleAssetsMember_11f0cd3a-d173-4074-8492-b4aef1cc5678_terseLabel_en-US" xlink:label="lab_us-gaap_OtherIntangibleAssetsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Software licenses [Member]</link:label>
    <link:label id="lab_us-gaap_OtherIntangibleAssetsMember_label_en-US" xlink:label="lab_us-gaap_OtherIntangibleAssetsMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Other Intangible Assets [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherIntangibleAssetsMember" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherIntangibleAssetsMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherIntangibleAssetsMember" xlink:to="lab_us-gaap_OtherIntangibleAssetsMember" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_RemainingAccrualMember_78ab6878-9647-4e52-84eb-c600f2a3cb28_terseLabel_en-US" xlink:label="lab_sigi_RemainingAccrualMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Remaining Accrual [Member]</link:label>
    <link:label id="lab_sigi_RemainingAccrualMember_label_en-US" xlink:label="lab_sigi_RemainingAccrualMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Remaining Accrual [Member]</link:label>
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    <link:label id="lab_srt_SupplementaryInsuranceInformationBySegmentTable_22de372d-bbef-4805-ad58-ab24377a37d5_terseLabel_en-US" xlink:label="lab_srt_SupplementaryInsuranceInformationBySegmentTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information [Table]</link:label>
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    <link:label id="lab_us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperations_aa3dfb37-d00c-4ef1-bf70-800508899e4b_totalLabel_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInInvestingActivitiesContinuingOperations" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Net cash used in investing activities</link:label>
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    <link:label id="lab_us-gaap_InterestExpenseDebt_477b6508-4340-4d5b-bb6a-08319ed11974_terseLabel_en-US" xlink:label="lab_us-gaap_InterestExpenseDebt" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Interest expense</link:label>
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    <link:label id="lab_us-gaap_InterestExpenseDebt_label_en-US" xlink:label="lab_us-gaap_InterestExpenseDebt" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Interest Expense, Debt</link:label>
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    <link:label id="lab_us-gaap_ShortDurationInsuranceContractAccidentYear2021Member_ac0dccf3-492c-486c-8a2c-351e48773bab_terseLabel_en-US" xlink:label="lab_us-gaap_ShortDurationInsuranceContractAccidentYear2021Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Short-Duration Insurance Contract, Accident Year 2021</link:label>
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    <link:label id="lab_sigi_ScheduleofShareBasedCompensationESPPandASPPSharesGrantedLineItems_b87f068c-e452-48ca-8e0a-3e77673b3840_terseLabel_en-US" xlink:label="lab_sigi_ScheduleofShareBasedCompensationESPPandASPPSharesGrantedLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule of Share-Based Compensation ESPP and ASPP Shares Granted [Line Items]</link:label>
    <link:label id="lab_sigi_ScheduleofShareBasedCompensationESPPandASPPSharesGrantedLineItems_label_en-US" xlink:label="lab_sigi_ScheduleofShareBasedCompensationESPPandASPPSharesGrantedLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule of Share-Based Compensation ESPP and ASPP Shares Granted [Line Items]</link:label>
    <link:label id="lab_sigi_ScheduleofShareBasedCompensationESPPandASPPSharesGrantedLineItems_documentation_en-US" xlink:label="lab_sigi_ScheduleofShareBasedCompensationESPPandASPPSharesGrantedLineItems" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">[Line Items] for Tabular disclosure of schedule of Share-Based Compensation ESPP and ASPP Shares Granted</link:label>
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    <link:label id="lab_us-gaap_EarningsPerShareDilutedAbstract_ba5b404a-72bf-4fa9-b6bc-e24296d082f2_terseLabel_en-US" xlink:label="lab_us-gaap_EarningsPerShareDilutedAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Earnings Per Share, Diluted [Abstract]</link:label>
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    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareDilutedAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EarningsPerShareDilutedAbstract"/>
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    <link:label id="lab_us-gaap_FairValueDisclosureItemAmountsDomain_670c5076-0b0d-4b35-8710-078830d8b352_terseLabel_en-US" xlink:label="lab_us-gaap_FairValueDisclosureItemAmountsDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Fair Value, Disclosure Item Amounts [Domain]</link:label>
    <link:label id="lab_us-gaap_FairValueDisclosureItemAmountsDomain_label_en-US" xlink:label="lab_us-gaap_FairValueDisclosureItemAmountsDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Fair Value Measurement [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueDisclosureItemAmountsDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueDisclosureItemAmountsDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FairValueDisclosureItemAmountsDomain" xlink:to="lab_us-gaap_FairValueDisclosureItemAmountsDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_ScheduleOfValuationAndQualifyingAccountsDisclosureTextBlock_8f99c2c1-33a1-4f70-808e-8d63b08cfc04_terseLabel_en-US" xlink:label="lab_srt_ScheduleOfValuationAndQualifyingAccountsDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule V - Allowance for Uncollectible Premiums and Other Receivables</link:label>
    <link:label id="lab_srt_ScheduleOfValuationAndQualifyingAccountsDisclosureTextBlock_label_en-US" xlink:label="lab_srt_ScheduleOfValuationAndQualifyingAccountsDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">SEC Schedule, 12-09, Schedule of Valuation and Qualifying Accounts Disclosure [Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ScheduleOfValuationAndQualifyingAccountsDisclosureTextBlock" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ScheduleOfValuationAndQualifyingAccountsDisclosureTextBlock"/>
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    <link:label id="lab_sigi_InvestmentExpensesMember_84a3d431-d1a5-46aa-ad9f-66681cf5c88c_terseLabel_en-US" xlink:label="lab_sigi_InvestmentExpensesMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Investment Expenses [Member]</link:label>
    <link:label id="lab_sigi_InvestmentExpensesMember_label_en-US" xlink:label="lab_sigi_InvestmentExpensesMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Investment Expenses [Member]</link:label>
    <link:label id="lab_sigi_InvestmentExpensesMember_documentation_en-US" xlink:label="lab_sigi_InvestmentExpensesMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">This represents expenses incurred in connection with fund investing and obtaining investment income.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_InvestmentExpensesMember" xlink:href="sigi-20211231.xsd#sigi_InvestmentExpensesMember"/>
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    <link:label id="lab_sigi_ReinsuranceRecoverableAllowanceForCreditLossesTable_aaf973d9-3115-40e5-bc2a-9a91bf1ab517_terseLabel_en-US" xlink:label="lab_sigi_ReinsuranceRecoverableAllowanceForCreditLossesTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Reinsurance Recoverable, Allowance for Credit Losses [Table]</link:label>
    <link:label id="lab_sigi_ReinsuranceRecoverableAllowanceForCreditLossesTable_label_en-US" xlink:label="lab_sigi_ReinsuranceRecoverableAllowanceForCreditLossesTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Reinsurance Recoverable, Allowance for Credit Losses [Table]</link:label>
    <link:label id="lab_sigi_ReinsuranceRecoverableAllowanceForCreditLossesTable_documentation_en-US" xlink:label="lab_sigi_ReinsuranceRecoverableAllowanceForCreditLossesTable" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Reinsurance Recoverable, Allowance for Credit Losses [Table]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_ReinsuranceRecoverableAllowanceForCreditLossesTable" xlink:href="sigi-20211231.xsd#sigi_ReinsuranceRecoverableAllowanceForCreditLossesTable"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_ReinsuranceRecoverableAllowanceForCreditLossesTable" xlink:to="lab_sigi_ReinsuranceRecoverableAllowanceForCreditLossesTable" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember_0f78228d-82e4-4b06-b93e-be2aacea36d8_terseLabel_en-US" xlink:label="lab_srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Cumulative Effect, Period of Adoption, Adjustment</link:label>
    <link:label id="lab_srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember_label_en-US" xlink:label="lab_srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Cumulative Effect, Period of Adoption, Adjustment [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_CumulativeEffectPeriodOfAdoptionAdjustmentMember"/>
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    <link:label id="lab_us-gaap_DefinedBenefitPlanAssetsForPlanBenefitsNoncurrent_f2de1b93-b293-4815-abca-996358d3ceac_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanAssetsForPlanBenefitsNoncurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Assets</link:label>
    <link:label id="lab_us-gaap_DefinedBenefitPlanAssetsForPlanBenefitsNoncurrent_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanAssetsForPlanBenefitsNoncurrent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Assets for Plan Benefits, Defined Benefit Plan</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanAssetsForPlanBenefitsNoncurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DefinedBenefitPlanAssetsForPlanBenefitsNoncurrent"/>
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    <link:label id="lab_us-gaap_ReinsuranceRecoverablesGross_label_en-US" xlink:label="lab_us-gaap_ReinsuranceRecoverablesGross" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Reinsurance Recoverables, Gross</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReinsuranceRecoverablesGross" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ReinsuranceRecoverablesGross"/>
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    <link:label id="lab_sigi_TotalNonRatedReinsurerMember_3cc35a40-6408-4355-8d0d-ee71a5eaed08_terseLabel_en-US" xlink:label="lab_sigi_TotalNonRatedReinsurerMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Total Non Rated Reinsurer [Member]</link:label>
    <link:label id="lab_sigi_TotalNonRatedReinsurerMember_label_en-US" xlink:label="lab_sigi_TotalNonRatedReinsurerMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Total Non Rated Reinsurer [Member]</link:label>
    <link:label id="lab_sigi_TotalNonRatedReinsurerMember_documentation_en-US" xlink:label="lab_sigi_TotalNonRatedReinsurerMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Total Non Rated Reinsurers rated by a rating agency.</link:label>
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    <link:label id="lab_sigi_AvailableForSaleSecuritiesScheduleTable_4436791e-ecaa-42ee-8d23-40d002a74de9_terseLabel_en-US" xlink:label="lab_sigi_AvailableForSaleSecuritiesScheduleTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule of Available-for-sale Securities [Table]</link:label>
    <link:label id="lab_sigi_AvailableForSaleSecuritiesScheduleTable_label_en-US" xlink:label="lab_sigi_AvailableForSaleSecuritiesScheduleTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Available For Sale Securities Schedule [Table]</link:label>
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    <link:loc xlink:type="locator" xlink:label="loc_sigi_AvailableForSaleSecuritiesScheduleTable" xlink:href="sigi-20211231.xsd#sigi_AvailableForSaleSecuritiesScheduleTable"/>
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    <link:label id="lab_us-gaap_CededCreditRiskAxis_896452b2-4c96-4c01-9f34-4fc56a1c328c_terseLabel_en-US" xlink:label="lab_us-gaap_CededCreditRiskAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Ceded Credit Risk [Axis]</link:label>
    <link:label id="lab_us-gaap_CededCreditRiskAxis_label_en-US" xlink:label="lab_us-gaap_CededCreditRiskAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Ceded Credit Risk, Reinsurer [Axis]</link:label>
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    <link:label id="lab_sigi_OmnibusStockPlan2014Member_documentation_en-US" xlink:label="lab_sigi_OmnibusStockPlan2014Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">An equity based payment arrangement in which one or more employees receive shares of stock (units), stock (unit) options, phantom stock, stock bonuses, stock appreciation rights, or other equity instruments for the 2014 plan.</link:label>
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    <link:label id="lab_us-gaap_IncomeTaxDisclosureAbstract_3c36b36c-4ad4-43aa-8b7b-3cc79c0d4477_terseLabel_en-US" xlink:label="lab_us-gaap_IncomeTaxDisclosureAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Income Tax Disclosure [Abstract]</link:label>
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    <link:label id="lab_dei_EntitySmallBusiness_4af0ce08-e192-4b69-9fae-6c6e680083a7_terseLabel_en-US" xlink:label="lab_dei_EntitySmallBusiness" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Entity Small Business</link:label>
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    <link:label id="lab_sigi_AuditAndEndorsementPremiumDecrease_c8b0b4fa-d5fa-4b15-bb69-070cf0d28e97_terseLabel_en-US" xlink:label="lab_sigi_AuditAndEndorsementPremiumDecrease" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Audit and Endorsement Premium</link:label>
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    <link:label id="lab_us-gaap_AdditionalCashFlowElementsAndSupplementalCashFlowInformationAbstract_label_en-US" xlink:label="lab_us-gaap_AdditionalCashFlowElementsAndSupplementalCashFlowInformationAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Additional Cash Flow Elements and Supplemental Cash Flow Information [Abstract]</link:label>
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    <link:label id="lab_us-gaap_ShortdurationInsuranceContractsScheduleOfHistoricalClaimsDurationTableTextBlock_d0abc36f-9e89-4701-a751-bf63bf0657f4_terseLabel_en-US" xlink:label="lab_us-gaap_ShortdurationInsuranceContractsScheduleOfHistoricalClaimsDurationTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule of Short-duration Insurance Contracts, Schedule of Historical Claims Duration</link:label>
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    <link:label id="lab_srt_StatementScenarioAxis_503b4eae-ed98-4136-896a-26956c11e439_terseLabel_en-US" xlink:label="lab_srt_StatementScenarioAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Scenario [Axis]</link:label>
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    <link:label id="lab_sigi_ComprehensiveIncomeLossBeforeTax_documentation_en-US" xlink:label="lab_sigi_ComprehensiveIncomeLossBeforeTax" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">The pre-tax change in equity [net assets] of a business enterprise during a period from transactions and other events and circumstances from non-owner sources which are attributable to the reporting entity. It includes all changes in equity during a period except those resulting from investments by owners and distributions to owners, but excludes any and all transactions which are directly or indirectly attributable to that ownership interest in subsidiary equity which is not attributable to the parent.</link:label>
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    <link:label id="lab_us-gaap_FederalHomeLoanBankAdvances_82b4eccd-e89a-4472-ab47-6208f99a2398_terseLabel_en-US" xlink:label="lab_us-gaap_FederalHomeLoanBankAdvances" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Federal Home Loan Bank Advances</link:label>
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    <link:label id="lab_us-gaap_LiabilitiesAndStockholdersEquityAbstract_1982025d-288e-4750-baa8-9e4755515d3a_terseLabel_en-US" xlink:label="lab_us-gaap_LiabilitiesAndStockholdersEquityAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">LIABILITIES AND STOCKHOLDERS&#8217; EQUITY</link:label>
    <link:label id="lab_us-gaap_LiabilitiesAndStockholdersEquityAbstract_d2d63985-801f-4daf-9e0d-5d308ba81cdb_verboseLabel_en-US" xlink:label="lab_us-gaap_LiabilitiesAndStockholdersEquityAbstract" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Liabilities:</link:label>
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    <link:label id="lab_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryTable_64df4585-d77b-49a1-be0b-8feda5adfa96_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Investment Income [Table]</link:label>
    <link:label id="lab_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryTable_label_en-US" xlink:label="lab_us-gaap_ScheduleOfInvestmentIncomeReportedAmountsByCategoryTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Investment Income [Table]</link:label>
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    <link:label id="lab_us-gaap_MortgageBackedSecuritiesMember_13ea9498-e52f-4880-a4cd-d72a05ffe760_terseLabel_en-US" xlink:label="lab_us-gaap_MortgageBackedSecuritiesMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">CLO and Other ABS</link:label>
    <link:label id="lab_us-gaap_MortgageBackedSecuritiesMember_label_en-US" xlink:label="lab_us-gaap_MortgageBackedSecuritiesMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Collateralized Mortgage Backed Securities [Member]</link:label>
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    <link:label id="lab_sigi_MaturitiesofLeaseLiabilitiesAbstract_label_en-US" xlink:label="lab_sigi_MaturitiesofLeaseLiabilitiesAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Maturities of Lease Liabilities [Abstract]</link:label>
    <link:label id="lab_sigi_MaturitiesofLeaseLiabilitiesAbstract_documentation_en-US" xlink:label="lab_sigi_MaturitiesofLeaseLiabilitiesAbstract" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Maturities of Lease Liabilities [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_MaturitiesofLeaseLiabilitiesAbstract" xlink:href="sigi-20211231.xsd#sigi_MaturitiesofLeaseLiabilitiesAbstract"/>
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    <link:label id="lab_sigi_IncreaseInDPWFromPriorYear_10b45bbe-a231-49d8-87ba-86ea19e01188_terseLabel_en-US" xlink:label="lab_sigi_IncreaseInDPWFromPriorYear" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Increase in DPW from Prior Year</link:label>
    <link:label id="lab_sigi_IncreaseInDPWFromPriorYear_label_en-US" xlink:label="lab_sigi_IncreaseInDPWFromPriorYear" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Increase in DPW from Prior Year</link:label>
    <link:label id="lab_sigi_IncreaseInDPWFromPriorYear_documentation_en-US" xlink:label="lab_sigi_IncreaseInDPWFromPriorYear" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">The increase in direct premiums written for the current year compared to the prior year.</link:label>
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    <link:label id="lab_sigi_PercentageCommonStockOwnedbyRelatedParty_dddb2c7d-d219-41ca-be15-56757702cfe6_terseLabel_en-US" xlink:label="lab_sigi_PercentageCommonStockOwnedbyRelatedParty" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Percentage Common Stock Owned by Related Party</link:label>
    <link:label id="lab_sigi_PercentageCommonStockOwnedbyRelatedParty_label_en-US" xlink:label="lab_sigi_PercentageCommonStockOwnedbyRelatedParty" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Percentage Common Stock Owned by Related Party</link:label>
    <link:label id="lab_sigi_PercentageCommonStockOwnedbyRelatedParty_documentation_en-US" xlink:label="lab_sigi_PercentageCommonStockOwnedbyRelatedParty" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Percentage of common stock owned by a related party</link:label>
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    <link:label id="lab_us-gaap_FairValueAssetsMeasuredOnRecurringAndNonrecurringBasisTableTextBlock_14a4a314-85d2-4fa3-b84b-2e628de2887e_terseLabel_en-US" xlink:label="lab_us-gaap_FairValueAssetsMeasuredOnRecurringAndNonrecurringBasisTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule of Quantitative Disclosures of our Financial Assets that were Measured at Fair Value</link:label>
    <link:label id="lab_us-gaap_FairValueAssetsMeasuredOnRecurringAndNonrecurringBasisTableTextBlock_label_en-US" xlink:label="lab_us-gaap_FairValueAssetsMeasuredOnRecurringAndNonrecurringBasisTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Fair Value, Assets Measured on Recurring and Nonrecurring Basis [Table Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueAssetsMeasuredOnRecurringAndNonrecurringBasisTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueAssetsMeasuredOnRecurringAndNonrecurringBasisTableTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FairValueAssetsMeasuredOnRecurringAndNonrecurringBasisTableTextBlock" xlink:to="lab_us-gaap_FairValueAssetsMeasuredOnRecurringAndNonrecurringBasisTableTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_BalanceSheetLocationDomain_7c5dbc70-0088-4aeb-8ef8-b1c6958a4507_terseLabel_en-US" xlink:label="lab_us-gaap_BalanceSheetLocationDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Balance Sheet Location [Domain]</link:label>
    <link:label id="lab_us-gaap_BalanceSheetLocationDomain_label_en-US" xlink:label="lab_us-gaap_BalanceSheetLocationDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Balance Sheet Location [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BalanceSheetLocationDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_BalanceSheetLocationDomain" xlink:to="lab_us-gaap_BalanceSheetLocationDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresMultipleAmount_fb1925d1-4659-448d-87d5-df82f242f72a_terseLabel_en-US" xlink:label="lab_sigi_FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresMultipleAmount" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Borrowing threshold of FHLBI</link:label>
    <link:label id="lab_sigi_FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresMultipleAmount_label_en-US" xlink:label="lab_sigi_FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresMultipleAmount" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Federal Home Loan Bank Advances General Debt Obligations Disclosures Multiple Amount</link:label>
    <link:label id="lab_sigi_FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresMultipleAmount_documentation_en-US" xlink:label="lab_sigi_FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresMultipleAmount" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">This amount is a multiple of the Company's aggregate investment in the Federal Home Loan Bank representing the Company's ability to borrow from the Federal Home Loan Bank.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresMultipleAmount" xlink:href="sigi-20211231.xsd#sigi_FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresMultipleAmount"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresMultipleAmount" xlink:to="lab_sigi_FederalHomeLoanBankAdvancesGeneralDebtObligationsDisclosuresMultipleAmount" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_UnearnedPremiums_3d762b1e-77f3-4227-a7f0-1925c8aa99ec_terseLabel_en-US" xlink:label="lab_us-gaap_UnearnedPremiums" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Unearned premiums</link:label>
    <link:label id="lab_us-gaap_UnearnedPremiums_label_en-US" xlink:label="lab_us-gaap_UnearnedPremiums" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Unearned Premiums</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnearnedPremiums" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_UnearnedPremiums"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_UnearnedPremiums" xlink:to="lab_us-gaap_UnearnedPremiums" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_FloodCededPremiumsAndLossesDomain_49c56c79-0d32-47fd-bd6a-7d7646412a6a_terseLabel_en-US" xlink:label="lab_sigi_FloodCededPremiumsAndLossesDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Flood Ceded Premiums and Losses [Domain]</link:label>
    <link:label id="lab_sigi_FloodCededPremiumsAndLossesDomain_label_en-US" xlink:label="lab_sigi_FloodCededPremiumsAndLossesDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Flood Ceded Premiums And Losses [Domain]</link:label>
    <link:label id="lab_sigi_FloodCededPremiumsAndLossesDomain_documentation_en-US" xlink:label="lab_sigi_FloodCededPremiumsAndLossesDomain" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Information pertaining to premiums and loss and loss expenses ceded to the National Flood Insurance Program.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_FloodCededPremiumsAndLossesDomain" xlink:href="sigi-20211231.xsd#sigi_FloodCededPremiumsAndLossesDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_FloodCededPremiumsAndLossesDomain" xlink:to="lab_sigi_FloodCededPremiumsAndLossesDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DeferredTaxAssetsGross_24a0376c-4ec1-46f6-be85-3676a6652710_totalLabel_en-US" xlink:label="lab_us-gaap_DeferredTaxAssetsGross" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Total deferred tax assets</link:label>
    <link:label id="lab_us-gaap_DeferredTaxAssetsGross_label_en-US" xlink:label="lab_us-gaap_DeferredTaxAssetsGross" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Deferred Tax Assets, Gross</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredTaxAssetsGross" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredTaxAssetsGross"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DeferredTaxAssetsGross" xlink:to="lab_us-gaap_DeferredTaxAssetsGross" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_EntityCommonStockSharesOutstanding_7c6dc700-49e5-4c0a-8056-2b0402e0026e_terseLabel_en-US" xlink:label="lab_dei_EntityCommonStockSharesOutstanding" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Entity Common Stock, Shares Outstanding</link:label>
    <link:label id="lab_dei_EntityCommonStockSharesOutstanding_label_en-US" xlink:label="lab_dei_EntityCommonStockSharesOutstanding" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Entity Common Stock, Shares Outstanding</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityCommonStockSharesOutstanding" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityCommonStockSharesOutstanding"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_EntityCommonStockSharesOutstanding" xlink:to="lab_dei_EntityCommonStockSharesOutstanding" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax_f2c53ecd-4569-4636-8f99-4ba91e13ddb9_terseLabel_en-US" xlink:label="lab_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax</link:label>
    <link:label id="lab_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax_label_en-US" xlink:label="lab_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Debt Securities, Available-for-sale, Accumulated Gross Unrealized Gain, before Tax</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax" xlink:to="lab_us-gaap_AvailableForSaleDebtSecuritiesAccumulatedGrossUnrealizedGainBeforeTax" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_DocumentAndEntityInformationAbstract_de3edb87-5078-4388-b2bf-1ad3e6742630_terseLabel_en-US" xlink:label="lab_sigi_DocumentAndEntityInformationAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Document and Entity Information [Abstract]</link:label>
    <link:label id="lab_sigi_DocumentAndEntityInformationAbstract_label_en-US" xlink:label="lab_sigi_DocumentAndEntityInformationAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Document and Entity Information [Abstract]</link:label>
    <link:label id="lab_sigi_DocumentAndEntityInformationAbstract_documentation_en-US" xlink:label="lab_sigi_DocumentAndEntityInformationAbstract" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Document and Entity Information [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_DocumentAndEntityInformationAbstract" xlink:href="sigi-20211231.xsd#sigi_DocumentAndEntityInformationAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_DocumentAndEntityInformationAbstract" xlink:to="lab_sigi_DocumentAndEntityInformationAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_EntityAddressStateOrProvince_a7843500-f946-49b1-aab8-253b511be717_terseLabel_en-US" xlink:label="lab_dei_EntityAddressStateOrProvince" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Entity Address, State or Province</link:label>
    <link:label id="lab_dei_EntityAddressStateOrProvince_label_en-US" xlink:label="lab_dei_EntityAddressStateOrProvince" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Entity Address, State or Province</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressStateOrProvince" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityAddressStateOrProvince"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_EntityAddressStateOrProvince" xlink:to="lab_dei_EntityAddressStateOrProvince" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_SupplementaryInsuranceInformationOtherOperatingExpense_366681a1-efa6-4bc5-aaa7-e42a3056fa96_terseLabel_en-US" xlink:label="lab_us-gaap_SupplementaryInsuranceInformationOtherOperatingExpense" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Other operating expenses</link:label>
    <link:label id="lab_us-gaap_SupplementaryInsuranceInformationOtherOperatingExpense_label_en-US" xlink:label="lab_us-gaap_SupplementaryInsuranceInformationOtherOperatingExpense" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Other Operating Expense</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SupplementaryInsuranceInformationOtherOperatingExpense" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SupplementaryInsuranceInformationOtherOperatingExpense"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SupplementaryInsuranceInformationOtherOperatingExpense" xlink:to="lab_us-gaap_SupplementaryInsuranceInformationOtherOperatingExpense" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_DividendsPaidToParentTable_33f70144-9529-438c-841f-95ec13734a66_terseLabel_en-US" xlink:label="lab_sigi_DividendsPaidToParentTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Dividends Paid To Parent [Table]</link:label>
    <link:label id="lab_sigi_DividendsPaidToParentTable_label_en-US" xlink:label="lab_sigi_DividendsPaidToParentTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Dividends Paid To Parent [Table]</link:label>
    <link:label id="lab_sigi_DividendsPaidToParentTable_documentation_en-US" xlink:label="lab_sigi_DividendsPaidToParentTable" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Disclosure of the dividends paid to the parent by an insurance subsidiary table.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_DividendsPaidToParentTable" xlink:href="sigi-20211231.xsd#sigi_DividendsPaidToParentTable"/>
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    <link:label id="lab_us-gaap_FairValueDisclosureOfAssetAndLiabilityNotMeasuredAtFairValueTableTextBlock_90fcf222-58bb-4b3b-8534-e4f87c9ad163_terseLabel_en-US" xlink:label="lab_us-gaap_FairValueDisclosureOfAssetAndLiabilityNotMeasuredAtFairValueTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule of Quantitative Information of our Financial Assets and Liabilities that were Disclosed at Fair Value</link:label>
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    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueDisclosureOfAssetAndLiabilityNotMeasuredAtFairValueTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueDisclosureOfAssetAndLiabilityNotMeasuredAtFairValueTableTextBlock"/>
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    <link:label id="lab_us-gaap_DeferredPolicyAcquisitionCostAmortizationExpense_0807f91c-b93d-46ef-9f40-a8176ac7afb8_terseLabel_en-US" xlink:label="lab_us-gaap_DeferredPolicyAcquisitionCostAmortizationExpense" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Amortization of deferred policy acquisition costs</link:label>
    <link:label id="lab_us-gaap_DeferredPolicyAcquisitionCostAmortizationExpense_label_en-US" xlink:label="lab_us-gaap_DeferredPolicyAcquisitionCostAmortizationExpense" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Deferred Policy Acquisition Costs, Amortization Expense</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredPolicyAcquisitionCostAmortizationExpense" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredPolicyAcquisitionCostAmortizationExpense"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DeferredPolicyAcquisitionCostAmortizationExpense" xlink:to="lab_us-gaap_DeferredPolicyAcquisitionCostAmortizationExpense" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_BorrowingsFromSubsidiaries_896b9ff8-a1e9-40e9-bfa0-ee7b33e3454c_terseLabel_en-US" xlink:label="lab_sigi_BorrowingsFromSubsidiaries" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Proceeds from borrowings</link:label>
    <link:label id="lab_sigi_BorrowingsFromSubsidiaries_label_en-US" xlink:label="lab_sigi_BorrowingsFromSubsidiaries" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Borrowings From Subsidiaries</link:label>
    <link:label id="lab_sigi_BorrowingsFromSubsidiaries_documentation_en-US" xlink:label="lab_sigi_BorrowingsFromSubsidiaries" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">The cash inflow from a borrowing made from the parent's subsidiaries.</link:label>
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    <link:label id="lab_us-gaap_DeferredIncomeTaxAssetsNet_d2eeeecb-3226-4e78-b87e-eb8120a655b7_terseLabel_en-US" xlink:label="lab_us-gaap_DeferredIncomeTaxAssetsNet" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Deferred federal income tax (Note 14)</link:label>
    <link:label id="lab_us-gaap_DeferredIncomeTaxAssetsNet_d1e92f52-014d-4443-8ddf-a7725dbb66c4_negatedTotalLabel_en-US" xlink:label="lab_us-gaap_DeferredIncomeTaxAssetsNet" xlink:role="http://www.xbrl.org/2009/role/negatedTotalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Deferred federal income tax</link:label>
    <link:label id="lab_us-gaap_DeferredIncomeTaxAssetsNet_de18073c-6a40-42ee-a529-b81a606ec2d6_verboseLabel_en-US" xlink:label="lab_us-gaap_DeferredIncomeTaxAssetsNet" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Deferred federal income tax</link:label>
    <link:label id="lab_us-gaap_DeferredIncomeTaxAssetsNet_label_en-US" xlink:label="lab_us-gaap_DeferredIncomeTaxAssetsNet" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Deferred Income Tax Assets, Net</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredIncomeTaxAssetsNet" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredIncomeTaxAssetsNet"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DeferredIncomeTaxAssetsNet" xlink:to="lab_us-gaap_DeferredIncomeTaxAssetsNet" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_LesseeDisclosureTextBlock_37a6fa93-6f43-4139-8191-2df9290d8d4f_terseLabel_en-US" xlink:label="lab_sigi_LesseeDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Lessee Disclosure [Text Block]</link:label>
    <link:label id="lab_sigi_LesseeDisclosureTextBlock_label_en-US" xlink:label="lab_sigi_LesseeDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Lessee Disclosure [Text Block]</link:label>
    <link:label id="lab_sigi_LesseeDisclosureTextBlock_documentation_en-US" xlink:label="lab_sigi_LesseeDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">The entire disclosure for finance and operating leases of a lessee</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_LesseeDisclosureTextBlock" xlink:href="sigi-20211231.xsd#sigi_LesseeDisclosureTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_LesseeDisclosureTextBlock" xlink:to="lab_sigi_LesseeDisclosureTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesCurrentAndNoncurrent_6dbff2a4-07c0-4f2c-aecb-24a8943c0572_verboseLabel_en-US" xlink:label="lab_us-gaap_PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesCurrentAndNoncurrent" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Liabilities</link:label>
    <link:label id="lab_us-gaap_PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesCurrentAndNoncurrent_label_en-US" xlink:label="lab_us-gaap_PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesCurrentAndNoncurrent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Liability, Defined Benefit Plan</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesCurrentAndNoncurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesCurrentAndNoncurrent"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesCurrentAndNoncurrent" xlink:to="lab_us-gaap_PensionAndOtherPostretirementDefinedBenefitPlansLiabilitiesCurrentAndNoncurrent" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_ESLinesMember_9c9bae2e-3b0f-4b33-9249-67ebedad481f_terseLabel_en-US" xlink:label="lab_sigi_ESLinesMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">E&amp;S Lines [Member]</link:label>
    <link:label id="lab_sigi_ESLinesMember_label_en-US" xlink:label="lab_sigi_ESLinesMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">E&amp;S Lines [Member]</link:label>
    <link:label id="lab_sigi_ESLinesMember_documentation_en-US" xlink:label="lab_sigi_ESLinesMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">This represents our E&amp;S Lines of business</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_ESLinesMember" xlink:href="sigi-20211231.xsd#sigi_ESLinesMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_ESLinesMember" xlink:to="lab_sigi_ESLinesMember" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_ReinsuranceRecoverableAxis_90c54686-31ef-4631-9f75-ec9093691649_terseLabel_en-US" xlink:label="lab_sigi_ReinsuranceRecoverableAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Reinsurance Recoverable [Axis]</link:label>
    <link:label id="lab_sigi_ReinsuranceRecoverableAxis_label_en-US" xlink:label="lab_sigi_ReinsuranceRecoverableAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Reinsurance Recoverable [Axis]</link:label>
    <link:label id="lab_sigi_ReinsuranceRecoverableAxis_documentation_en-US" xlink:label="lab_sigi_ReinsuranceRecoverableAxis" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Reinsurance Recoverable [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_ReinsuranceRecoverableAxis" xlink:href="sigi-20211231.xsd#sigi_ReinsuranceRecoverableAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_ReinsuranceRecoverableAxis" xlink:to="lab_sigi_ReinsuranceRecoverableAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice_5db4c671-0476-45db-9415-3fdc0511a557_terseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Exercisable as December 31, 2019, weighted average exercise price</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice" xlink:to="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisableWeightedAverageExercisePrice" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_IncreaseDecreaseInPremiumsReceivable_662cf026-4c49-4bea-8058-602fcaa4645a_negatedLabel_en-US" xlink:label="lab_us-gaap_IncreaseDecreaseInPremiumsReceivable" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Increase in premiums receivable</link:label>
    <link:label id="lab_us-gaap_IncreaseDecreaseInPremiumsReceivable_label_en-US" xlink:label="lab_us-gaap_IncreaseDecreaseInPremiumsReceivable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Increase (Decrease) in Premiums Receivable</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInPremiumsReceivable" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncreaseDecreaseInPremiumsReceivable"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncreaseDecreaseInPremiumsReceivable" xlink:to="lab_us-gaap_IncreaseDecreaseInPremiumsReceivable" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_ConversionOfAFSFixedIncomeSecuritiesToEquitySecurities_5e3102fd-5c68-4d94-a51e-e76e4b995306_terseLabel_en-US" xlink:label="lab_sigi_ConversionOfAFSFixedIncomeSecuritiesToEquitySecurities" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Conversion of AFS fixed income securities to equity securities</link:label>
    <link:label id="lab_sigi_ConversionOfAFSFixedIncomeSecuritiesToEquitySecurities_label_en-US" xlink:label="lab_sigi_ConversionOfAFSFixedIncomeSecuritiesToEquitySecurities" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Conversion of AFS fixed income securities to equity securities</link:label>
    <link:label id="lab_sigi_ConversionOfAFSFixedIncomeSecuritiesToEquitySecurities_documentation_en-US" xlink:label="lab_sigi_ConversionOfAFSFixedIncomeSecuritiesToEquitySecurities" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Conversion of AFS fixed income securities to equity securities</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_ConversionOfAFSFixedIncomeSecuritiesToEquitySecurities" xlink:href="sigi-20211231.xsd#sigi_ConversionOfAFSFixedIncomeSecuritiesToEquitySecurities"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_ConversionOfAFSFixedIncomeSecuritiesToEquitySecurities" xlink:to="lab_sigi_ConversionOfAFSFixedIncomeSecuritiesToEquitySecurities" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_EquitySecuritiesMember_f2dc0936-5679-4917-9229-3ab7b6942ddf_terseLabel_en-US" xlink:label="lab_us-gaap_EquitySecuritiesMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Equity Securities [Member]</link:label>
    <link:label id="lab_us-gaap_EquitySecuritiesMember_label_en-US" xlink:label="lab_us-gaap_EquitySecuritiesMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Equity Securities [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquitySecuritiesMember" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquitySecuritiesMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EquitySecuritiesMember" xlink:to="lab_us-gaap_EquitySecuritiesMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AccountingPoliciesAbstract_4319496e-3a3d-488a-9d60-7d2fa1fddd63_terseLabel_en-US" xlink:label="lab_us-gaap_AccountingPoliciesAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Accounting Policies [Abstract]</link:label>
    <link:label id="lab_us-gaap_AccountingPoliciesAbstract_label_en-US" xlink:label="lab_us-gaap_AccountingPoliciesAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Accounting Policies [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccountingPoliciesAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccountingPoliciesAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AccountingPoliciesAbstract" xlink:to="lab_us-gaap_AccountingPoliciesAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFour_ad5b96bd-c8b1-4648-88fd-54c181f9ea22_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFour" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">2024</link:label>
    <link:label id="lab_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFour_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFour" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Defined Benefit Plan, Expected Future Benefit Payment, Year Four</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFour" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFour"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFour" xlink:to="lab_us-gaap_DefinedBenefitPlanExpectedFutureBenefitPaymentsYearFour" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ForeignGovernmentDebtSecuritiesMember_bb67cc00-c228-4313-9516-908b35e4b5aa_terseLabel_en-US" xlink:label="lab_us-gaap_ForeignGovernmentDebtSecuritiesMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Foreign Government [Member]</link:label>
    <link:label id="lab_us-gaap_ForeignGovernmentDebtSecuritiesMember_label_en-US" xlink:label="lab_us-gaap_ForeignGovernmentDebtSecuritiesMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Debt Security, Government, Non-US [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ForeignGovernmentDebtSecuritiesMember" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ForeignGovernmentDebtSecuritiesMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ForeignGovernmentDebtSecuritiesMember" xlink:to="lab_us-gaap_ForeignGovernmentDebtSecuritiesMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ContractualObligation_04176ccc-a29a-48f0-814e-b033ad470a9f_terseLabel_en-US" xlink:label="lab_us-gaap_ContractualObligation" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Contractual Obligation</link:label>
    <link:label id="lab_us-gaap_ContractualObligation_label_en-US" xlink:label="lab_us-gaap_ContractualObligation" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Contractual Obligation</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ContractualObligation" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ContractualObligation"/>
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    <link:label id="lab_sigi_TerrorismRiskInsuranceProgramInsurerRetainer_b7e75ae4-6fbb-4c7f-a46a-d7d14724c607_terseLabel_en-US" xlink:label="lab_sigi_TerrorismRiskInsuranceProgramInsurerRetainer" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Terrorism Risk Insurance Program Insurer Retainer</link:label>
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    <link:label id="lab_sigi_TerrorismRiskInsuranceProgramInsurerRetainer_documentation_en-US" xlink:label="lab_sigi_TerrorismRiskInsuranceProgramInsurerRetainer" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">The percentage that the insured has to pay for losses under the Terrorism Risk Insurance Program, beginning the next calendar year.</link:label>
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    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLiability" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingLeaseLiability"/>
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    <link:label id="lab_us-gaap_CommonStockValue_a9fb1343-84a2-40a2-9e88-0ec29f0cced6_terseLabel_en-US" xlink:label="lab_us-gaap_CommonStockValue" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Common stock of $2 par value per share Authorized shares: 360,000,000 Issued: 104,450,916 - 2021; 104,032,912 - 2020</link:label>
    <link:label id="lab_us-gaap_CommonStockValue_label_en-US" xlink:label="lab_us-gaap_CommonStockValue" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Common Stock, Value, Issued</link:label>
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    <link:label id="lab_sigi_Totalleaseliabilitynotyetcommenced_cfb13452-7364-4eaa-9d24-aa5b5c4b0f9f_terseLabel_en-US" xlink:label="lab_sigi_Totalleaseliabilitynotyetcommenced" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Total lease liability not yet commenced</link:label>
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    <link:label id="lab_us-gaap_SummaryOfInvestmentsOtherThanInvestmentsInRelatedPartiesCarryingAmount_label_en-US" xlink:label="lab_us-gaap_SummaryOfInvestmentsOtherThanInvestmentsInRelatedPartiesCarryingAmount" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties, Amount</link:label>
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    <link:label id="lab_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_743cf841-d8e1-4998-bb25-332469ab5694_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule of Property, Plant and Equipment [Table]</link:label>
    <link:label id="lab_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable_label_en-US" xlink:label="lab_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Property, Plant and Equipment [Table]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfPropertyPlantAndEquipmentTable" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfPropertyPlantAndEquipmentTable"/>
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    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfAvailableForSaleSecuritiesLineItems"/>
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    <link:label id="lab_sigi_NewJerseyDividendRestriction_43e48970-030d-45c5-9dd4-de6cc157ba8a_terseLabel_en-US" xlink:label="lab_sigi_NewJerseyDividendRestriction" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">New Jersey Dividend Restriction</link:label>
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    <link:label id="lab_sigi_CommercialPropertyMember_1e353b02-5c63-4149-8564-03c958734d40_terseLabel_en-US" xlink:label="lab_sigi_CommercialPropertyMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Commercial Property [Member]</link:label>
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    <link:label id="lab_sigi_CommercialPropertyMember_documentation_en-US" xlink:label="lab_sigi_CommercialPropertyMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Commercial property line of business within Standard Commercial Lines segment.</link:label>
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    <link:label id="lab_us-gaap_BanksTrustAndInsuranceEquitiesMember_9c3e1c7e-1e4f-408f-8791-4180ef7b884a_terseLabel_en-US" xlink:label="lab_us-gaap_BanksTrustAndInsuranceEquitiesMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Banks, trusts, and insurance companies</link:label>
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    <link:label id="lab_us-gaap_OperatingCostsAndExpenses_76204eba-6c27-4b1f-9453-da7cd4b55f1f_terseLabel_en-US" xlink:label="lab_us-gaap_OperatingCostsAndExpenses" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Corporate expenses</link:label>
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    <link:label id="lab_us-gaap_LossContingencyNatureDomain_6e190544-64d5-4f0c-a80e-ea82e6b7cb73_terseLabel_en-US" xlink:label="lab_us-gaap_LossContingencyNatureDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Loss Contingency, Nature [Domain]</link:label>
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    <link:label id="lab_sigi_ESPropertyLinesMember_6fef0f34-73f5-41b2-8860-df864e033e6c_terseLabel_en-US" xlink:label="lab_sigi_ESPropertyLinesMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">E&amp;S Property Lines [Member]</link:label>
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    <link:label id="lab_sigi_IncreaseDecreaseInUnearnedPremiumsNetOfPrepaidReinsurance_6c21457a-b966-4559-a4e7-65d9f79c2bb1_terseLabel_en-US" xlink:label="lab_sigi_IncreaseDecreaseInUnearnedPremiumsNetOfPrepaidReinsurance" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Increase in unearned premiums, net of prepaid reinsurance</link:label>
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    <link:label id="lab_sigi_LiabilityHedgingAssetsMember_33ae734a-c7ec-4c3e-a84d-403264aea060_terseLabel_en-US" xlink:label="lab_sigi_LiabilityHedgingAssetsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Liability Hedging Assets [Member]</link:label>
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    <link:label id="lab_us-gaap_AmountRecognizedInNetPeriodicBenefitCostAndOtherComprehensiveIncomeLossBeforeTax_a1b7bc34-d7a2-4fba-ad6e-92e2c550ac98_totalLabel_en-US" xlink:label="lab_us-gaap_AmountRecognizedInNetPeriodicBenefitCostAndOtherComprehensiveIncomeLossBeforeTax" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Total recognized in net periodic benefit cost and OCI</link:label>
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    <link:label id="lab_sigi_AccruedLongTermStockCompensation_0f99df9c-6c2c-4c8b-ae47-0ba4267a9eac_terseLabel_en-US" xlink:label="lab_sigi_AccruedLongTermStockCompensation" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Accrued long-term stock compensation</link:label>
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    <link:label id="lab_sigi_AccruedLongTermStockCompensation_documentation_en-US" xlink:label="lab_sigi_AccruedLongTermStockCompensation" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Represents our long term stock compensation accrued liability</link:label>
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    <link:label id="lab_us-gaap_AwardTypeAxis_fc0b4b94-5915-4f6f-aa68-da2a686924c5_terseLabel_en-US" xlink:label="lab_us-gaap_AwardTypeAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Award Type [Axis]</link:label>
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    <link:label id="lab_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_4a26a413-72e2-4976-8790-6a45f573f3b5_terseLabel_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Financing Activities</link:label>
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    <link:label id="lab_us-gaap_StockholdersEquity_c4a2b4b0-d303-4e85-bef9-626d0e6a24b2_totalLabel_en-US" xlink:label="lab_us-gaap_StockholdersEquity" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Total stockholders&#8217; equity</link:label>
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    <link:label id="lab_dei_CityAreaCode_3de552e8-f308-4d81-95e7-d611defe8c46_terseLabel_en-US" xlink:label="lab_dei_CityAreaCode" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">City Area Code</link:label>
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    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfDefinedBenefitPlansDisclosuresTable"/>
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    <link:label id="lab_us-gaap_AsbestosIssueMember_043b2a50-bcde-41e9-9494-e309f5d7561e_terseLabel_en-US" xlink:label="lab_us-gaap_AsbestosIssueMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Asbestos [Member]</link:label>
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    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AsbestosIssueMember" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AsbestosIssueMember"/>
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    <link:label id="lab_us-gaap_RestrictedStockUnitsRSUMember_5cb85f9c-1a2b-45b1-b450-64417efc62e8_terseLabel_en-US" xlink:label="lab_us-gaap_RestrictedStockUnitsRSUMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Restricted Stock Units (RSUs) [Member]</link:label>
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    <link:label id="lab_us-gaap_FinanceLeaseLiability_7966ed1e-d8be-46a8-903c-fa6f933a1830_verboseLabel_en-US" xlink:label="lab_us-gaap_FinanceLeaseLiability" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Finance lease, Long-term debt</link:label>
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    <link:label id="lab_us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseAccumulatedUnallocatedClaimAdjustmentExpense_6c703d7c-31d1-42cf-9638-fefed458223d_terseLabel_en-US" xlink:label="lab_us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseAccumulatedUnallocatedClaimAdjustmentExpense" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Unallocated loss expenses</link:label>
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    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseAccumulatedUnallocatedClaimAdjustmentExpense" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShortdurationInsuranceContractsLiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseAccumulatedUnallocatedClaimAdjustmentExpense"/>
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    <link:label id="lab_sigi_AsbestosClaimMember_documentation_en-US" xlink:label="lab_sigi_AsbestosClaimMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Asbestos Claim [Member]</link:label>
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    <link:label id="lab_us-gaap_PropertyPlantAndEquipmentTypeDomain_5462164e-26a4-423c-91b4-19652a025268_terseLabel_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentTypeDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Property, Plant and Equipment, Type [Domain]</link:label>
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    <link:label id="lab_us-gaap_FairValueByBalanceSheetGroupingTable_12bc5f33-4dba-4de7-b3ef-311e17c71828_terseLabel_en-US" xlink:label="lab_us-gaap_FairValueByBalanceSheetGroupingTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Fair Value, by Balance Sheet Grouping [Table]</link:label>
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    <link:label id="lab_us-gaap_ScheduleOfCashAndCashEquivalentsTableTextBlock_e960b08f-3407-4026-9f57-41c95edb4314_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfCashAndCashEquivalentsTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule of Cash and Cash Equivalents</link:label>
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    <link:label id="lab_sigi_USTreasuryFundMember_d96fce1f-ccb9-4528-8021-1e4d1565e782_terseLabel_en-US" xlink:label="lab_sigi_USTreasuryFundMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">US Treasury Securities [Member]</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_SwissReGroupMember" xlink:to="lab_sigi_SwissReGroupMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_445cc3d4-4a30-4699-8fd2-2c3f2b41985f_terseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Options, weighted average grant date fair value</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:to="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodWeightedAverageGrantDateFairValue" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_RemainingUnsecuredReinsuranceNetofCollateralMember_526604e3-868d-4c58-9e96-ee9d2017a6b5_terseLabel_en-US" xlink:label="lab_sigi_RemainingUnsecuredReinsuranceNetofCollateralMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Remaining Unsecured Reinsurance, Net of Collateral [Member]</link:label>
    <link:label id="lab_sigi_RemainingUnsecuredReinsuranceNetofCollateralMember_label_en-US" xlink:label="lab_sigi_RemainingUnsecuredReinsuranceNetofCollateralMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Remaining Unsecured Reinsurance, Net of Collateral [Member]</link:label>
    <link:label id="lab_sigi_RemainingUnsecuredReinsuranceNetofCollateralMember_documentation_en-US" xlink:label="lab_sigi_RemainingUnsecuredReinsuranceNetofCollateralMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Represents the net unsecured reinsurance balance less all federal and state pools, and collateral.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_RemainingUnsecuredReinsuranceNetofCollateralMember" xlink:href="sigi-20211231.xsd#sigi_RemainingUnsecuredReinsuranceNetofCollateralMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_RemainingUnsecuredReinsuranceNetofCollateralMember" xlink:to="lab_sigi_RemainingUnsecuredReinsuranceNetofCollateralMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_EquityComponentDomain_9ef79434-19c3-4568-8d17-c48b8dcc0174_terseLabel_en-US" xlink:label="lab_us-gaap_EquityComponentDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Equity Component [Domain]</link:label>
    <link:label id="lab_us-gaap_EquityComponentDomain_label_en-US" xlink:label="lab_us-gaap_EquityComponentDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Equity Component [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityComponentDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityComponentDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EquityComponentDomain" xlink:to="lab_us-gaap_EquityComponentDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsOutstandingNumber_d73f8482-50e1-4619-87b5-8158a656ffc4_terseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsOutstandingNumber" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding, Number</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsOutstandingNumber_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsOutstandingNumber" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award, Non-Option Equity Instruments, Outstanding, Number</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsOutstandingNumber" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsOutstandingNumber"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsOutstandingNumber" xlink:to="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNonOptionEquityInstrumentsOutstandingNumber" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems_5bb26a2a-cabd-4241-acc8-6dbde800b085_terseLabel_en-US" xlink:label="lab_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Financing Receivable, Allowance for Credit Loss [Line Items]</link:label>
    <link:label id="lab_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems_label_en-US" xlink:label="lab_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Financing Receivable, Allowance for Credit Loss [Line Items]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems" xlink:to="lab_us-gaap_FinancingReceivableAllowanceForCreditLossesLineItems" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_StatutoryAccountingPracticesStatutoryUnassignedSurplus_3e3e1aa2-a118-4550-b983-ccc2f323c1a1_terseLabel_en-US" xlink:label="lab_sigi_StatutoryAccountingPracticesStatutoryUnassignedSurplus" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Statutory unassigned surplus</link:label>
    <link:label id="lab_sigi_StatutoryAccountingPracticesStatutoryUnassignedSurplus_label_en-US" xlink:label="lab_sigi_StatutoryAccountingPracticesStatutoryUnassignedSurplus" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Statutory Accounting Practices Statutory Unassigned Surplus</link:label>
    <link:label id="lab_sigi_StatutoryAccountingPracticesStatutoryUnassignedSurplus_documentation_en-US" xlink:label="lab_sigi_StatutoryAccountingPracticesStatutoryUnassignedSurplus" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">The amount of statutory unassigned surplus as of the balance sheet date using prescribed or permitted statutory accounting practices (rather than GAAP, if different) of the state or country.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_StatutoryAccountingPracticesStatutoryUnassignedSurplus" xlink:href="sigi-20211231.xsd#sigi_StatutoryAccountingPracticesStatutoryUnassignedSurplus"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_StatutoryAccountingPracticesStatutoryUnassignedSurplus" xlink:to="lab_sigi_StatutoryAccountingPracticesStatutoryUnassignedSurplus" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths_04890b1d-aae2-4e6a-8e4a-820811926a0f_terseLabel_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Operating Lease Liability, Due Year One</link:label>
    <link:label id="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths_label_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Lessee, Operating Lease, Liability, to be Paid, Year One</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths" xlink:to="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueNextTwelveMonths" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_CollateralOfReinsuranceRecoverables_e14397f9-26f6-429b-b692-7597c1c253e4_negatedLabel_en-US" xlink:label="lab_sigi_CollateralOfReinsuranceRecoverables" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Less: collateral</link:label>
    <link:label id="lab_sigi_CollateralOfReinsuranceRecoverables_label_en-US" xlink:label="lab_sigi_CollateralOfReinsuranceRecoverables" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Collateral Of Reinsurance Recoverables</link:label>
    <link:label id="lab_sigi_CollateralOfReinsuranceRecoverables_documentation_en-US" xlink:label="lab_sigi_CollateralOfReinsuranceRecoverables" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">This element represents the amount collateralized by the entity's reinsurers. The amount includes letters of credit, trust funds, and funds withheld.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_CollateralOfReinsuranceRecoverables" xlink:href="sigi-20211231.xsd#sigi_CollateralOfReinsuranceRecoverables"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_CollateralOfReinsuranceRecoverables" xlink:to="lab_sigi_CollateralOfReinsuranceRecoverables" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_MortgageLoansOnRealEstateCommercialAndConsumerNet_1b1c6d55-4025-4cb5-a43f-f667ff426bc2_totalLabel_en-US" xlink:label="lab_us-gaap_MortgageLoansOnRealEstateCommercialAndConsumerNet" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Commercial mortgage loans, net of allowance for credit losses</link:label>
    <link:label id="lab_us-gaap_MortgageLoansOnRealEstateCommercialAndConsumerNet_label_en-US" xlink:label="lab_us-gaap_MortgageLoansOnRealEstateCommercialAndConsumerNet" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Mortgage Loans on Real Estate, Commercial and Consumer, Net</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_MortgageLoansOnRealEstateCommercialAndConsumerNet" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_MortgageLoansOnRealEstateCommercialAndConsumerNet"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_MortgageLoansOnRealEstateCommercialAndConsumerNet" xlink:to="lab_us-gaap_MortgageLoansOnRealEstateCommercialAndConsumerNet" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_SupplementaryInsuranceInformationForInsuranceCompaniesDisclosureTextBlock_030c5714-066e-47c2-9f30-ef46951d43e2_terseLabel_en-US" xlink:label="lab_srt_SupplementaryInsuranceInformationForInsuranceCompaniesDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule III- Supplementary Insurance Information</link:label>
    <link:label id="lab_srt_SupplementaryInsuranceInformationForInsuranceCompaniesDisclosureTextBlock_label_en-US" xlink:label="lab_srt_SupplementaryInsuranceInformationForInsuranceCompaniesDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Disclosure [Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_SupplementaryInsuranceInformationForInsuranceCompaniesDisclosureTextBlock" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_SupplementaryInsuranceInformationForInsuranceCompaniesDisclosureTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_SupplementaryInsuranceInformationForInsuranceCompaniesDisclosureTextBlock" xlink:to="lab_srt_SupplementaryInsuranceInformationForInsuranceCompaniesDisclosureTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_SelectiveInsuranceCompanyOfNewEnglandMember_c29439c1-3854-4537-b3dd-0d6cf464ca86_terseLabel_en-US" xlink:label="lab_sigi_SelectiveInsuranceCompanyOfNewEnglandMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Selective Insurance Company of New England (SICNE) [Member]</link:label>
    <link:label id="lab_sigi_SelectiveInsuranceCompanyOfNewEnglandMember_5cd01daa-9a97-463e-bb6f-9d192a485e14_verboseLabel_en-US" xlink:label="lab_sigi_SelectiveInsuranceCompanyOfNewEnglandMember" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Selective Insurance Company of New England (SICNE) [Member]</link:label>
    <link:label id="lab_sigi_SelectiveInsuranceCompanyOfNewEnglandMember_label_en-US" xlink:label="lab_sigi_SelectiveInsuranceCompanyOfNewEnglandMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Selective Insurance Company of New England [Member]</link:label>
    <link:label id="lab_sigi_SelectiveInsuranceCompanyOfNewEnglandMember_documentation_en-US" xlink:label="lab_sigi_SelectiveInsuranceCompanyOfNewEnglandMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">This item represents Selective Insurance Company of New England, a subsidiary of the Parent.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_SelectiveInsuranceCompanyOfNewEnglandMember" xlink:href="sigi-20211231.xsd#sigi_SelectiveInsuranceCompanyOfNewEnglandMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_SelectiveInsuranceCompanyOfNewEnglandMember" xlink:to="lab_sigi_SelectiveInsuranceCompanyOfNewEnglandMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis_c0d8c416-5b0b-425f-bc72-0e78792cd0f4_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Defined Benefit Plan, Plan Assets, Category [Axis]</link:label>
    <link:label id="lab_us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis_label_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Defined Benefit Plan, Plan Assets, Category [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis" xlink:to="lab_us-gaap_DefinedBenefitPlanByPlanAssetCategoriesAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_DebtInstrumentDiscount_5bcce8d8-c584-421b-903f-7469d6c6be23_terseLabel_en-US" xlink:label="lab_sigi_DebtInstrumentDiscount" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Discount for notes issued</link:label>
    <link:label id="lab_sigi_DebtInstrumentDiscount_label_en-US" xlink:label="lab_sigi_DebtInstrumentDiscount" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Debt Instrument Discount</link:label>
    <link:label id="lab_sigi_DebtInstrumentDiscount_documentation_en-US" xlink:label="lab_sigi_DebtInstrumentDiscount" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">The amount of debt discount that was originally recognized at the issuance of the instrument.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_DebtInstrumentDiscount" xlink:href="sigi-20211231.xsd#sigi_DebtInstrumentDiscount"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_DebtInstrumentDiscount" xlink:to="lab_sigi_DebtInstrumentDiscount" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_ScheduleOfFairValueAndGrossPreTaxUnrealizedUnrecognizedLossOfSecuritiesByLengthOfTimeDomain_23d6470f-162f-4ffc-9b7c-e3f8c873ab99_terseLabel_en-US" xlink:label="lab_sigi_ScheduleOfFairValueAndGrossPreTaxUnrealizedUnrecognizedLossOfSecuritiesByLengthOfTimeDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule Of Fair Value And Gross Pre Tax Unrealized Unrecognized Loss Of Securities By Length Of Time [Domain]</link:label>
    <link:label id="lab_sigi_ScheduleOfFairValueAndGrossPreTaxUnrealizedUnrecognizedLossOfSecuritiesByLengthOfTimeDomain_label_en-US" xlink:label="lab_sigi_ScheduleOfFairValueAndGrossPreTaxUnrealizedUnrecognizedLossOfSecuritiesByLengthOfTimeDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule Of Fair Value And Gross Pre Tax Unrealized Unrecognized Loss Of Securities By Length Of Time [Domain]</link:label>
    <link:label id="lab_sigi_ScheduleOfFairValueAndGrossPreTaxUnrealizedUnrecognizedLossOfSecuritiesByLengthOfTimeDomain_documentation_en-US" xlink:label="lab_sigi_ScheduleOfFairValueAndGrossPreTaxUnrealizedUnrecognizedLossOfSecuritiesByLengthOfTimeDomain" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Provides general categories of securities that are in a continuous loss position.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_ScheduleOfFairValueAndGrossPreTaxUnrealizedUnrecognizedLossOfSecuritiesByLengthOfTimeDomain" xlink:href="sigi-20211231.xsd#sigi_ScheduleOfFairValueAndGrossPreTaxUnrealizedUnrecognizedLossOfSecuritiesByLengthOfTimeDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_ScheduleOfFairValueAndGrossPreTaxUnrealizedUnrecognizedLossOfSecuritiesByLengthOfTimeDomain" xlink:to="lab_sigi_ScheduleOfFairValueAndGrossPreTaxUnrealizedUnrecognizedLossOfSecuritiesByLengthOfTimeDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AccruedSalariesCurrentAndNoncurrent_b65ebc9c-2f36-4644-8851-e80cd2e44007_terseLabel_en-US" xlink:label="lab_us-gaap_AccruedSalariesCurrentAndNoncurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Accrued salaries and benefits</link:label>
    <link:label id="lab_us-gaap_AccruedSalariesCurrentAndNoncurrent_label_en-US" xlink:label="lab_us-gaap_AccruedSalariesCurrentAndNoncurrent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Accrued Salaries</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccruedSalariesCurrentAndNoncurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccruedSalariesCurrentAndNoncurrent"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AccruedSalariesCurrentAndNoncurrent" xlink:to="lab_us-gaap_AccruedSalariesCurrentAndNoncurrent" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_ReinsurancePremiumsForInsuranceCompaniesByProductSegmentTable_0511b9bd-939a-4ac3-aaed-b15ce3087e8b_terseLabel_en-US" xlink:label="lab_srt_ReinsurancePremiumsForInsuranceCompaniesByProductSegmentTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">SEC Schedule, 12-17, Insurance Companies, Reinsurance [Table]</link:label>
    <link:label id="lab_srt_ReinsurancePremiumsForInsuranceCompaniesByProductSegmentTable_label_en-US" xlink:label="lab_srt_ReinsurancePremiumsForInsuranceCompaniesByProductSegmentTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">SEC Schedule, 12-17, Insurance Companies, Reinsurance [Table]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ReinsurancePremiumsForInsuranceCompaniesByProductSegmentTable" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ReinsurancePremiumsForInsuranceCompaniesByProductSegmentTable"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_ReinsurancePremiumsForInsuranceCompaniesByProductSegmentTable" xlink:to="lab_srt_ReinsurancePremiumsForInsuranceCompaniesByProductSegmentTable" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DeferredFinanceCostsGross_98168948-ef22-4d35-8262-074bd50eed69_terseLabel_en-US" xlink:label="lab_us-gaap_DeferredFinanceCostsGross" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Debt Issuance Costs, Gross</link:label>
    <link:label id="lab_us-gaap_DeferredFinanceCostsGross_label_en-US" xlink:label="lab_us-gaap_DeferredFinanceCostsGross" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Debt Issuance Costs, Gross</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredFinanceCostsGross" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredFinanceCostsGross"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DeferredFinanceCostsGross" xlink:to="lab_us-gaap_DeferredFinanceCostsGross" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_SupplementalLeaseInformationAbstract_1d54638d-c156-46c1-9a6b-10e611f08edc_terseLabel_en-US" xlink:label="lab_sigi_SupplementalLeaseInformationAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Supplemental Lease Information [Abstract]</link:label>
    <link:label id="lab_sigi_SupplementalLeaseInformationAbstract_label_en-US" xlink:label="lab_sigi_SupplementalLeaseInformationAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Supplemental Lease Information [Abstract]</link:label>
    <link:label id="lab_sigi_SupplementalLeaseInformationAbstract_documentation_en-US" xlink:label="lab_sigi_SupplementalLeaseInformationAbstract" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Supplemental Lease Information [Abstract]</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_SupplementalLeaseInformationAbstract" xlink:to="lab_sigi_SupplementalLeaseInformationAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_TotalFederalAndStatePoolsMember_6a0024fe-fb92-4f39-aa51-c0dae23b7319_terseLabel_en-US" xlink:label="lab_sigi_TotalFederalAndStatePoolsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Total Federal And State Pools [Member]</link:label>
    <link:label id="lab_sigi_TotalFederalAndStatePoolsMember_label_en-US" xlink:label="lab_sigi_TotalFederalAndStatePoolsMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Total Federal And State Pools [Member]</link:label>
    <link:label id="lab_sigi_TotalFederalAndStatePoolsMember_documentation_en-US" xlink:label="lab_sigi_TotalFederalAndStatePoolsMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Represents the total federal and state pools.</link:label>
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    <link:label id="lab_us-gaap_OtherIncome_1c669723-1626-4b8e-8f7b-dafc178d8bf3_terseLabel_en-US" xlink:label="lab_us-gaap_OtherIncome" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Other income</link:label>
    <link:label id="lab_us-gaap_OtherIncome_label_en-US" xlink:label="lab_us-gaap_OtherIncome" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Other Income</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherIncome" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherIncome"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherIncome" xlink:to="lab_us-gaap_OtherIncome" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_PreferredSharesLineItems_4fb27177-881a-479a-84a4-a9cca0b52a83_terseLabel_en-US" xlink:label="lab_sigi_PreferredSharesLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Treasury Stock[Line Items]</link:label>
    <link:label id="lab_sigi_PreferredSharesLineItems_label_en-US" xlink:label="lab_sigi_PreferredSharesLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Preferred Shares [Line Items]</link:label>
    <link:label id="lab_sigi_PreferredSharesLineItems_documentation_en-US" xlink:label="lab_sigi_PreferredSharesLineItems" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Preferred Shares [Line Items]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_PreferredSharesLineItems" xlink:href="sigi-20211231.xsd#sigi_PreferredSharesLineItems"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_PreferredSharesLineItems" xlink:to="lab_sigi_PreferredSharesLineItems" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_StatutoryDataAxis_ea5dafd2-f6d8-4568-95af-3c7f214846c0_terseLabel_en-US" xlink:label="lab_sigi_StatutoryDataAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Statutory Data [Axis]</link:label>
    <link:label id="lab_sigi_StatutoryDataAxis_label_en-US" xlink:label="lab_sigi_StatutoryDataAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Statutory Data [Axis]</link:label>
    <link:label id="lab_sigi_StatutoryDataAxis_documentation_en-US" xlink:label="lab_sigi_StatutoryDataAxis" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Disclosure of insurance subsidiaries' statutory surplus, unassigned surplus and statutory net income axis.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_StatutoryDataAxis" xlink:href="sigi-20211231.xsd#sigi_StatutoryDataAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_StatutoryDataAxis" xlink:to="lab_sigi_StatutoryDataAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ShortTermDebtTypeAxis_8258f46a-a628-4b15-b9b8-c23b27e95ae8_terseLabel_en-US" xlink:label="lab_us-gaap_ShortTermDebtTypeAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Short-term Debt, Type [Axis]</link:label>
    <link:label id="lab_us-gaap_ShortTermDebtTypeAxis_label_en-US" xlink:label="lab_us-gaap_ShortTermDebtTypeAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Short-term Debt, Type [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShortTermDebtTypeAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShortTermDebtTypeAxis" xlink:to="lab_us-gaap_ShortTermDebtTypeAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_HomeownersMember_d59eb3c0-2aa3-4b9b-a6c0-60fac1bc6f2e_terseLabel_en-US" xlink:label="lab_sigi_HomeownersMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Homeowners [Member]</link:label>
    <link:label id="lab_sigi_HomeownersMember_label_en-US" xlink:label="lab_sigi_HomeownersMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Homeowners [Member]</link:label>
    <link:label id="lab_sigi_HomeownersMember_documentation_en-US" xlink:label="lab_sigi_HomeownersMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Represents insurance coverage provided to policy holders on dwellings.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_HomeownersMember" xlink:href="sigi-20211231.xsd#sigi_HomeownersMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_HomeownersMember" xlink:to="lab_sigi_HomeownersMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ScheduleOfCompensationCostForShareBasedPaymentArrangementsAllocationOfShareBasedCompensationCostsByPlanTableTextBlock_db43ae70-a393-4ca6-bc9b-ce0086756cbc_verboseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfCompensationCostForShareBasedPaymentArrangementsAllocationOfShareBasedCompensationCostsByPlanTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule of Compensation Cost for Share-based Payment Arrangements</link:label>
    <link:label id="lab_us-gaap_ScheduleOfCompensationCostForShareBasedPaymentArrangementsAllocationOfShareBasedCompensationCostsByPlanTableTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfCompensationCostForShareBasedPaymentArrangementsAllocationOfShareBasedCompensationCostsByPlanTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Share-based Payment Arrangement, Cost by Plan [Table Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfCompensationCostForShareBasedPaymentArrangementsAllocationOfShareBasedCompensationCostsByPlanTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfCompensationCostForShareBasedPaymentArrangementsAllocationOfShareBasedCompensationCostsByPlanTableTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfCompensationCostForShareBasedPaymentArrangementsAllocationOfShareBasedCompensationCostsByPlanTableTextBlock" xlink:to="lab_us-gaap_ScheduleOfCompensationCostForShareBasedPaymentArrangementsAllocationOfShareBasedCompensationCostsByPlanTableTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ScheduleOfAllocationOfPlanAssetsTableTextBlock_0ba90146-acbb-4bea-80d6-51fb755aeea4_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfAllocationOfPlanAssetsTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule of Allocation of Plan Assets</link:label>
    <link:label id="lab_us-gaap_ScheduleOfAllocationOfPlanAssetsTableTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfAllocationOfPlanAssetsTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule of Allocation of Plan Assets [Table Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAllocationOfPlanAssetsTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfAllocationOfPlanAssetsTableTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfAllocationOfPlanAssetsTableTextBlock" xlink:to="lab_us-gaap_ScheduleOfAllocationOfPlanAssetsTableTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ShortTermInvestmentsMember_a4897586-e70b-47ee-a637-b77fd681f25a_terseLabel_en-US" xlink:label="lab_us-gaap_ShortTermInvestmentsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Short-term Investments [Member]</link:label>
    <link:label id="lab_us-gaap_ShortTermInvestmentsMember_label_en-US" xlink:label="lab_us-gaap_ShortTermInvestmentsMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Short-term Investments [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermInvestmentsMember" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShortTermInvestmentsMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShortTermInvestmentsMember" xlink:to="lab_us-gaap_ShortTermInvestmentsMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour_a4e7f0bb-7a7e-4021-a624-ffe3c2a14218_terseLabel_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Operating Lease Liability, Due Year Four</link:label>
    <link:label id="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour_label_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Lessee, Operating Lease, Liability, to be Paid, Year Four</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour" xlink:to="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFour" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_WeightedAverageMember_57c12d4b-59b5-4691-a9ac-de2018b09fd0_terseLabel_en-US" xlink:label="lab_srt_WeightedAverageMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Weighted Average</link:label>
    <link:label id="lab_srt_WeightedAverageMember_label_en-US" xlink:label="lab_srt_WeightedAverageMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Weighted Average [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_WeightedAverageMember" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_WeightedAverageMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_WeightedAverageMember" xlink:to="lab_srt_WeightedAverageMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_be1e8719-d340-427f-842b-efab3c46efde_totalLabel_en-US" xlink:label="lab_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Income before federal income tax</link:label>
    <link:label id="lab_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_643d4cec-6301-4a4a-a592-f55b2dae9156_terseLabel_en-US" xlink:label="lab_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Income before federal income tax</link:label>
    <link:label id="lab_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest_label_en-US" xlink:label="lab_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" xlink:to="lab_us-gaap_IncomeLossFromContinuingOperationsBeforeIncomeTaxesExtraordinaryItemsNoncontrollingInterest" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FairValueInputsLevel2Member_964694c8-e46a-4af9-b131-e31aab742e6c_terseLabel_en-US" xlink:label="lab_us-gaap_FairValueInputsLevel2Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Significant Other Observable Inputs (Level 2) [Member]</link:label>
    <link:label id="lab_us-gaap_FairValueInputsLevel2Member_label_en-US" xlink:label="lab_us-gaap_FairValueInputsLevel2Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Fair Value, Inputs, Level 2 [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueInputsLevel2Member" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueInputsLevel2Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FairValueInputsLevel2Member" xlink:to="lab_us-gaap_FairValueInputsLevel2Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_BenefitsLossesAndExpenses_4b7387c3-7c9d-4f2d-99f9-937f9981a883_totalLabel_en-US" xlink:label="lab_us-gaap_BenefitsLossesAndExpenses" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Total expenses</link:label>
    <link:label id="lab_us-gaap_BenefitsLossesAndExpenses_77d294e4-34fd-4d64-8403-64af40956728_terseLabel_en-US" xlink:label="lab_us-gaap_BenefitsLossesAndExpenses" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Total expenses</link:label>
    <link:label id="lab_us-gaap_BenefitsLossesAndExpenses_label_en-US" xlink:label="lab_us-gaap_BenefitsLossesAndExpenses" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Benefits, Losses and Expenses</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BenefitsLossesAndExpenses" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BenefitsLossesAndExpenses"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_BenefitsLossesAndExpenses" xlink:to="lab_us-gaap_BenefitsLossesAndExpenses" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LiabilityForCatastropheClaimsByCatastrophicEventAxis_2dd2e1b5-e556-47fc-9d7b-7bd51969330e_terseLabel_en-US" xlink:label="lab_us-gaap_LiabilityForCatastropheClaimsByCatastrophicEventAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Catastrophic Event [Axis]</link:label>
    <link:label id="lab_us-gaap_LiabilityForCatastropheClaimsByCatastrophicEventAxis_e3460406-946b-4017-b411-052e36377c15_verboseLabel_en-US" xlink:label="lab_us-gaap_LiabilityForCatastropheClaimsByCatastrophicEventAxis" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Axis]</link:label>
    <link:label id="lab_us-gaap_LiabilityForCatastropheClaimsByCatastrophicEventAxis_label_en-US" xlink:label="lab_us-gaap_LiabilityForCatastropheClaimsByCatastrophicEventAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Catastrophic Event [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilityForCatastropheClaimsByCatastrophicEventAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LiabilityForCatastropheClaimsByCatastrophicEventAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LiabilityForCatastropheClaimsByCatastrophicEventAxis" xlink:to="lab_us-gaap_LiabilityForCatastropheClaimsByCatastrophicEventAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_AuditorLocation_e985c794-2810-4ae8-9eb2-fc4c721a9f5c_terseLabel_en-US" xlink:label="lab_dei_AuditorLocation" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Auditor Location</link:label>
    <link:label id="lab_dei_AuditorLocation_label_en-US" xlink:label="lab_dei_AuditorLocation" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Auditor Location</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_AuditorLocation" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_AuditorLocation"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_AuditorLocation" xlink:to="lab_dei_AuditorLocation" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_PercentageOfNetUnsecuredReinsurance_bc665594-5602-4bb7-88e9-62d3955d3c77_terseLabel_en-US" xlink:label="lab_sigi_PercentageOfNetUnsecuredReinsurance" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">% of Net Unsecured Reinsurance</link:label>
    <link:label id="lab_sigi_PercentageOfNetUnsecuredReinsurance_label_en-US" xlink:label="lab_sigi_PercentageOfNetUnsecuredReinsurance" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Percentage Of Net Unsecured Reinsurance</link:label>
    <link:label id="lab_sigi_PercentageOfNetUnsecuredReinsurance_documentation_en-US" xlink:label="lab_sigi_PercentageOfNetUnsecuredReinsurance" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">This element represents the percentage of the total net unsecured reinsurance balance.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_PercentageOfNetUnsecuredReinsurance" xlink:href="sigi-20211231.xsd#sigi_PercentageOfNetUnsecuredReinsurance"/>
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    <link:label id="lab_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPosition_55c91176-21ce-455a-985a-b6f1d0d3708a_terseLabel_en-US" xlink:label="lab_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPosition" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Debt Securities, Available-for-sale, Unrealized Loss Position</link:label>
    <link:label id="lab_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPosition_label_en-US" xlink:label="lab_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPosition" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Debt Securities, Available-for-sale, Unrealized Loss Position</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPosition" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPosition"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPosition" xlink:to="lab_us-gaap_DebtSecuritiesAvailableForSaleUnrealizedLossPosition" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_SegmentReportingAbstract_575cba0f-3f7d-488e-b458-c9d4069a3e72_terseLabel_en-US" xlink:label="lab_us-gaap_SegmentReportingAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Segment Reporting [Abstract]</link:label>
    <link:label id="lab_us-gaap_SegmentReportingAbstract_label_en-US" xlink:label="lab_us-gaap_SegmentReportingAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Segment Reporting [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentReportingAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SegmentReportingAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SegmentReportingAbstract" xlink:to="lab_us-gaap_SegmentReportingAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis_fe3e07fb-a050-48d9-9082-714d199d5063_terseLabel_en-US" xlink:label="lab_us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Fixed income securities, Available-For-Sale, Amortized Cost</link:label>
    <link:label id="lab_us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis_label_en-US" xlink:label="lab_us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Debt Securities, Available-for-sale, Amortized Cost</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis" xlink:to="lab_us-gaap_AvailableForSaleDebtSecuritiesAmortizedCostBasis" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ScheduleOfEntityWideInformationRevenueFromExternalCustomersByProductsAndServicesTable_bc6105d9-3521-4c6d-908e-670f3ee13754_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfEntityWideInformationRevenueFromExternalCustomersByProductsAndServicesTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Revenue from External Customers by Products and Services [Table]</link:label>
    <link:label id="lab_us-gaap_ScheduleOfEntityWideInformationRevenueFromExternalCustomersByProductsAndServicesTable_label_en-US" xlink:label="lab_us-gaap_ScheduleOfEntityWideInformationRevenueFromExternalCustomersByProductsAndServicesTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Revenue from External Customers by Products and Services [Table]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfEntityWideInformationRevenueFromExternalCustomersByProductsAndServicesTable" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfEntityWideInformationRevenueFromExternalCustomersByProductsAndServicesTable"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfEntityWideInformationRevenueFromExternalCustomersByProductsAndServicesTable" xlink:to="lab_us-gaap_ScheduleOfEntityWideInformationRevenueFromExternalCustomersByProductsAndServicesTable" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FinanceLeaseInterestExpense_99c182d3-af89-4769-bcf9-3b78fbcbb359_terseLabel_en-US" xlink:label="lab_us-gaap_FinanceLeaseInterestExpense" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Finance lease cost: Interest on lease liabilities</link:label>
    <link:label id="lab_us-gaap_FinanceLeaseInterestExpense_label_en-US" xlink:label="lab_us-gaap_FinanceLeaseInterestExpense" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Finance Lease, Interest Expense</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseInterestExpense" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinanceLeaseInterestExpense"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FinanceLeaseInterestExpense" xlink:to="lab_us-gaap_FinanceLeaseInterestExpense" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperations_354b204d-f963-43b6-9e25-e4836d989689_totalLabel_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperations" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Net cash (used in) provided by financing activities</link:label>
    <link:label id="lab_us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperations_label_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperations" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Net Cash Provided by (Used in) Financing Activities, Continuing Operations</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperations" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperations"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperations" xlink:to="lab_us-gaap_NetCashProvidedByUsedInFinancingActivitiesContinuingOperations" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_UseOfEstimates_53d5fe8c-ee79-41ab-8a20-ea414f3642a2_terseLabel_en-US" xlink:label="lab_us-gaap_UseOfEstimates" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Use of Estimates</link:label>
    <link:label id="lab_us-gaap_UseOfEstimates_label_en-US" xlink:label="lab_us-gaap_UseOfEstimates" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Use of Estimates, Policy [Policy Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UseOfEstimates" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_UseOfEstimates"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_UseOfEstimates" xlink:to="lab_us-gaap_UseOfEstimates" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ScheduleOfEarningsPerShareBasicAndDilutedTableTextBlock_974d62a7-fef3-4a95-ae00-573a44264293_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfEarningsPerShareBasicAndDilutedTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule of Reconciliation of Earnings Per Share</link:label>
    <link:label id="lab_us-gaap_ScheduleOfEarningsPerShareBasicAndDilutedTableTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfEarningsPerShareBasicAndDilutedTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfEarningsPerShareBasicAndDilutedTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfEarningsPerShareBasicAndDilutedTableTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfEarningsPerShareBasicAndDilutedTableTextBlock" xlink:to="lab_us-gaap_ScheduleOfEarningsPerShareBasicAndDilutedTableTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_GeographicConcentrationOfNetPremiumsWrittenPercentage_d70bc050-88f4-4af3-81a5-de80a0b5249c_terseLabel_en-US" xlink:label="lab_sigi_GeographicConcentrationOfNetPremiumsWrittenPercentage" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Percentage of net premiums written related to insurance policies written in New Jersey</link:label>
    <link:label id="lab_sigi_GeographicConcentrationOfNetPremiumsWrittenPercentage_label_en-US" xlink:label="lab_sigi_GeographicConcentrationOfNetPremiumsWrittenPercentage" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Geographic Concentration Of Net Premiums Written Percentage</link:label>
    <link:label id="lab_sigi_GeographicConcentrationOfNetPremiumsWrittenPercentage_documentation_en-US" xlink:label="lab_sigi_GeographicConcentrationOfNetPremiumsWrittenPercentage" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">This item represents the geographic concentration of net premiums written, reflected as a percentage of New Jersey net written premiums compared to our total net premiums written.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_GeographicConcentrationOfNetPremiumsWrittenPercentage" xlink:href="sigi-20211231.xsd#sigi_GeographicConcentrationOfNetPremiumsWrittenPercentage"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_GeographicConcentrationOfNetPremiumsWrittenPercentage" xlink:to="lab_sigi_GeographicConcentrationOfNetPremiumsWrittenPercentage" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_PreferredSharesTable_00db259e-2273-4736-86b7-474a69ee2f47_terseLabel_en-US" xlink:label="lab_sigi_PreferredSharesTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Equity [Table]</link:label>
    <link:label id="lab_sigi_PreferredSharesTable_label_en-US" xlink:label="lab_sigi_PreferredSharesTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Preferred Shares [Table]</link:label>
    <link:label id="lab_sigi_PreferredSharesTable_documentation_en-US" xlink:label="lab_sigi_PreferredSharesTable" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Preferred Shares [Table]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_PreferredSharesTable" xlink:href="sigi-20211231.xsd#sigi_PreferredSharesTable"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_PreferredSharesTable" xlink:to="lab_sigi_PreferredSharesTable" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ReinsuranceRecoverableCreditQualityIndicatorTableTextBlock_715ac1a2-19aa-4a77-8151-7238aa7e4966_terseLabel_en-US" xlink:label="lab_us-gaap_ReinsuranceRecoverableCreditQualityIndicatorTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Reinsurance Recoverable, Credit Quality Indicator</link:label>
    <link:label id="lab_us-gaap_ReinsuranceRecoverableCreditQualityIndicatorTableTextBlock_label_en-US" xlink:label="lab_us-gaap_ReinsuranceRecoverableCreditQualityIndicatorTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Reinsurance Recoverable, Credit Quality Indicator [Table Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReinsuranceRecoverableCreditQualityIndicatorTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ReinsuranceRecoverableCreditQualityIndicatorTableTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ReinsuranceRecoverableCreditQualityIndicatorTableTextBlock" xlink:to="lab_us-gaap_ReinsuranceRecoverableCreditQualityIndicatorTableTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ReinsurancePremiumsForInsuranceCompaniesByProductSegmentNetAmountAbstract_6bcfbee5-643d-40fe-86c5-372be5c3f1f0_terseLabel_en-US" xlink:label="lab_us-gaap_ReinsurancePremiumsForInsuranceCompaniesByProductSegmentNetAmountAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Premiums Earned:</link:label>
    <link:label id="lab_us-gaap_ReinsurancePremiumsForInsuranceCompaniesByProductSegmentNetAmountAbstract_label_en-US" xlink:label="lab_us-gaap_ReinsurancePremiumsForInsuranceCompaniesByProductSegmentNetAmountAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Premiums Earned, Net [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReinsurancePremiumsForInsuranceCompaniesByProductSegmentNetAmountAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ReinsurancePremiumsForInsuranceCompaniesByProductSegmentNetAmountAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ReinsurancePremiumsForInsuranceCompaniesByProductSegmentNetAmountAbstract" xlink:to="lab_us-gaap_ReinsurancePremiumsForInsuranceCompaniesByProductSegmentNetAmountAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_Security12bTitle_8ec0fe67-efa7-4403-97cc-d455fce385b4_terseLabel_en-US" xlink:label="lab_dei_Security12bTitle" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Title of 12(b) Security</link:label>
    <link:label id="lab_dei_Security12bTitle_label_en-US" xlink:label="lab_dei_Security12bTitle" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Title of 12(b) Security</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_Security12bTitle" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_Security12bTitle"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_Security12bTitle" xlink:to="lab_dei_Security12bTitle" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_OtherSecuritiesMember_8a87cd0e-b610-4e75-9e73-6d46dbf55b48_terseLabel_en-US" xlink:label="lab_sigi_OtherSecuritiesMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Other Securities [Member]</link:label>
    <link:label id="lab_sigi_OtherSecuritiesMember_label_en-US" xlink:label="lab_sigi_OtherSecuritiesMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Other Securities [Member]</link:label>
    <link:label id="lab_sigi_OtherSecuritiesMember_documentation_en-US" xlink:label="lab_sigi_OtherSecuritiesMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">This represents all other other securities not otherwise specified.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_OtherSecuritiesMember" xlink:href="sigi-20211231.xsd#sigi_OtherSecuritiesMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_OtherSecuritiesMember" xlink:to="lab_sigi_OtherSecuritiesMember" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_StatutoryDataDomain_63dc8606-310c-4b40-9229-23debe406d41_terseLabel_en-US" xlink:label="lab_sigi_StatutoryDataDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Statutory Data [Domain]</link:label>
    <link:label id="lab_sigi_StatutoryDataDomain_label_en-US" xlink:label="lab_sigi_StatutoryDataDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Statutory Data [Domain]</link:label>
    <link:label id="lab_sigi_StatutoryDataDomain_documentation_en-US" xlink:label="lab_sigi_StatutoryDataDomain" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Disclosure of insurance subsidiaries' statutory surplus, unassigned surplus and statutory net income domain.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_StatutoryDataDomain" xlink:href="sigi-20211231.xsd#sigi_StatutoryDataDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_StatutoryDataDomain" xlink:to="lab_sigi_StatutoryDataDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RealizedInvestmentGainsLosses_5094cbd4-c473-4934-beaa-99566414098d_verboseLabel_en-US" xlink:label="lab_us-gaap_RealizedInvestmentGainsLosses" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Net realized and unrealized investment gains</link:label>
    <link:label id="lab_us-gaap_RealizedInvestmentGainsLosses_50907ea8-a222-4fd0-8520-e8a6c4a4ec96_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_RealizedInvestmentGainsLosses" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Net realized and unrealized investment gains</link:label>
    <link:label id="lab_us-gaap_RealizedInvestmentGainsLosses_label_en-US" xlink:label="lab_us-gaap_RealizedInvestmentGainsLosses" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Realized Investment Gains (Losses)</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RealizedInvestmentGainsLosses" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RealizedInvestmentGainsLosses"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RealizedInvestmentGainsLosses" xlink:to="lab_us-gaap_RealizedInvestmentGainsLosses" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_ReturnauditandmidtermendorsementpremiumMember_d2de4248-e739-4535-9213-97d914162271_terseLabel_en-US" xlink:label="lab_sigi_ReturnauditandmidtermendorsementpremiumMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Return audit and midterm endorsement premium [Member]</link:label>
    <link:label id="lab_sigi_ReturnauditandmidtermendorsementpremiumMember_label_en-US" xlink:label="lab_sigi_ReturnauditandmidtermendorsementpremiumMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Return audit and midterm endorsement premium [Member]</link:label>
    <link:label id="lab_sigi_ReturnauditandmidtermendorsementpremiumMember_documentation_en-US" xlink:label="lab_sigi_ReturnauditandmidtermendorsementpremiumMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">The amount of return audit and mid-term endorsement premium accrual adjustment in the period.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_ReturnauditandmidtermendorsementpremiumMember" xlink:href="sigi-20211231.xsd#sigi_ReturnauditandmidtermendorsementpremiumMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_ReturnauditandmidtermendorsementpremiumMember" xlink:to="lab_sigi_ReturnauditandmidtermendorsementpremiumMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_CommonStockSharesAuthorized_6e70f3c2-bfd1-4195-a45f-3022ae569fba_terseLabel_en-US" xlink:label="lab_us-gaap_CommonStockSharesAuthorized" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Common Stock, Shares Authorized</link:label>
    <link:label id="lab_us-gaap_CommonStockSharesAuthorized_label_en-US" xlink:label="lab_us-gaap_CommonStockSharesAuthorized" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Common Stock, Shares Authorized</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockSharesAuthorized" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommonStockSharesAuthorized"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CommonStockSharesAuthorized" xlink:to="lab_us-gaap_CommonStockSharesAuthorized" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_FinanceleaseobligationMember_dc005341-f2a8-477e-880c-c911b903e48c_terseLabel_en-US" xlink:label="lab_sigi_FinanceleaseobligationMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Finance lease obligation [Member]</link:label>
    <link:label id="lab_sigi_FinanceleaseobligationMember_label_en-US" xlink:label="lab_sigi_FinanceleaseobligationMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Finance lease obligation [Member]</link:label>
    <link:label id="lab_sigi_FinanceleaseobligationMember_documentation_en-US" xlink:label="lab_sigi_FinanceleaseobligationMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Present value of lessee's discounted obligation for lease payments from finance lease.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_FinanceleaseobligationMember" xlink:href="sigi-20211231.xsd#sigi_FinanceleaseobligationMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_FinanceleaseobligationMember" xlink:to="lab_sigi_FinanceleaseobligationMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic_84eab18e-7936-4f0e-b130-5f257da6a54d_totalLabel_en-US" xlink:label="lab_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Net Income available to common stockholders</link:label>
    <link:label id="lab_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic_1a9cf138-c38c-4fe1-b751-fe4c60bea516_terseLabel_en-US" xlink:label="lab_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Net Income available to common stockholders</link:label>
    <link:label id="lab_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic_label_en-US" xlink:label="lab_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Net Income (Loss) Available to Common Stockholders, Basic</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic" xlink:to="lab_us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_DocumentType_701cdefc-e221-4126-96e6-efca27b02416_terseLabel_en-US" xlink:label="lab_dei_DocumentType" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Document Type</link:label>
    <link:label id="lab_dei_DocumentType_label_en-US" xlink:label="lab_dei_DocumentType" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Document Type</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentType" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_DocumentType"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_DocumentType" xlink:to="lab_dei_DocumentType" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_SelectiveFireAndCasualtyInsuranceCompanyMember_70207c6a-80c5-4674-b9e2-98ca72c829c6_terseLabel_en-US" xlink:label="lab_sigi_SelectiveFireAndCasualtyInsuranceCompanyMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Selective Fire and Casualty Insurance Company (SFCIC) [Member]</link:label>
    <link:label id="lab_sigi_SelectiveFireAndCasualtyInsuranceCompanyMember_5de14b30-83cf-4600-8ec0-bb3a72f04847_verboseLabel_en-US" xlink:label="lab_sigi_SelectiveFireAndCasualtyInsuranceCompanyMember" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Selective Fire and Casualty Insurance Company (SFCIC) [Member]</link:label>
    <link:label id="lab_sigi_SelectiveFireAndCasualtyInsuranceCompanyMember_label_en-US" xlink:label="lab_sigi_SelectiveFireAndCasualtyInsuranceCompanyMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Selective Fire and Casualty Insurance Company [Member]</link:label>
    <link:label id="lab_sigi_SelectiveFireAndCasualtyInsuranceCompanyMember_documentation_en-US" xlink:label="lab_sigi_SelectiveFireAndCasualtyInsuranceCompanyMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">This item represents Selective Fire and Casualty Insurance Company, a subsidiary of the Parent.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_SelectiveFireAndCasualtyInsuranceCompanyMember" xlink:href="sigi-20211231.xsd#sigi_SelectiveFireAndCasualtyInsuranceCompanyMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_SelectiveFireAndCasualtyInsuranceCompanyMember" xlink:to="lab_sigi_SelectiveFireAndCasualtyInsuranceCompanyMember" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_EquityMethodInvestmentSummarizedFinancialInformationLiabilitiesSIGI_d09166fe-e701-4818-8052-f2010459f23e_terseLabel_en-US" xlink:label="lab_sigi_EquityMethodInvestmentSummarizedFinancialInformationLiabilitiesSIGI" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Liabilities</link:label>
    <link:label id="lab_sigi_EquityMethodInvestmentSummarizedFinancialInformationLiabilitiesSIGI_label_en-US" xlink:label="lab_sigi_EquityMethodInvestmentSummarizedFinancialInformationLiabilitiesSIGI" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Equity Method Investment, Summarized Financial Information, Liabilities SIGI</link:label>
    <link:label id="lab_sigi_EquityMethodInvestmentSummarizedFinancialInformationLiabilitiesSIGI_documentation_en-US" xlink:label="lab_sigi_EquityMethodInvestmentSummarizedFinancialInformationLiabilitiesSIGI" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">The amount of liabilities reported by an equity method investment of the entity.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_EquityMethodInvestmentSummarizedFinancialInformationLiabilitiesSIGI" xlink:href="sigi-20211231.xsd#sigi_EquityMethodInvestmentSummarizedFinancialInformationLiabilitiesSIGI"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_EquityMethodInvestmentSummarizedFinancialInformationLiabilitiesSIGI" xlink:to="lab_sigi_EquityMethodInvestmentSummarizedFinancialInformationLiabilitiesSIGI" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_PreferredStockDividendsPerShareDeclared_c91b9b6b-81a6-4ce5-9fbe-04e5b475e3e0_terseLabel_en-US" xlink:label="lab_us-gaap_PreferredStockDividendsPerShareDeclared" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Dividends declared per preferred share</link:label>
    <link:label id="lab_us-gaap_PreferredStockDividendsPerShareDeclared_label_en-US" xlink:label="lab_us-gaap_PreferredStockDividendsPerShareDeclared" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Preferred Stock, Dividends Per Share, Declared</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockDividendsPerShareDeclared" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PreferredStockDividendsPerShareDeclared"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PreferredStockDividendsPerShareDeclared" xlink:to="lab_us-gaap_PreferredStockDividendsPerShareDeclared" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_ProductsAndServicesDomain_f903dabc-cafe-4532-8dc0-df72d8250338_terseLabel_en-US" xlink:label="lab_srt_ProductsAndServicesDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Line of Business [Domain]</link:label>
    <link:label id="lab_srt_ProductsAndServicesDomain_9f198fad-4e04-4b0b-b27b-345cf763f620_verboseLabel_en-US" xlink:label="lab_srt_ProductsAndServicesDomain" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Reinsurance Premiums for Insurance Companies, by Product Segment [Domain]</link:label>
    <link:label id="lab_srt_ProductsAndServicesDomain_label_en-US" xlink:label="lab_srt_ProductsAndServicesDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Product and Service [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductsAndServicesDomain" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ProductsAndServicesDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_ProductsAndServicesDomain" xlink:to="lab_srt_ProductsAndServicesDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ScheduleOfLiabilityForUnpaidClaimsAndClaimsAdjustmentExpense_f7aa5ae9-bdb1-47b5-af9b-48fd7e9ea995_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfLiabilityForUnpaidClaimsAndClaimsAdjustmentExpense" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule of Roll Forward of Reserve for Loss and Loss Expense</link:label>
    <link:label id="lab_us-gaap_ScheduleOfLiabilityForUnpaidClaimsAndClaimsAdjustmentExpense_label_en-US" xlink:label="lab_us-gaap_ScheduleOfLiabilityForUnpaidClaimsAndClaimsAdjustmentExpense" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule of Liability for Unpaid Claims and Claims Adjustment Expense [Table Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfLiabilityForUnpaidClaimsAndClaimsAdjustmentExpense" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfLiabilityForUnpaidClaimsAndClaimsAdjustmentExpense"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfLiabilityForUnpaidClaimsAndClaimsAdjustmentExpense" xlink:to="lab_us-gaap_ScheduleOfLiabilityForUnpaidClaimsAndClaimsAdjustmentExpense" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_RelatedPartyTransactionsContributionsToFoundation_e422c20b-38a6-45a7-8723-0f32a062a85c_terseLabel_en-US" xlink:label="lab_sigi_RelatedPartyTransactionsContributionsToFoundation" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Contributions to the Selective Insurance Group Foundation</link:label>
    <link:label id="lab_sigi_RelatedPartyTransactionsContributionsToFoundation_label_en-US" xlink:label="lab_sigi_RelatedPartyTransactionsContributionsToFoundation" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Related Party Transactions Contributions To Foundation</link:label>
    <link:label id="lab_sigi_RelatedPartyTransactionsContributionsToFoundation_documentation_en-US" xlink:label="lab_sigi_RelatedPartyTransactionsContributionsToFoundation" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">The amount of contributions made to a related party private foundation.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_RelatedPartyTransactionsContributionsToFoundation" xlink:href="sigi-20211231.xsd#sigi_RelatedPartyTransactionsContributionsToFoundation"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_RelatedPartyTransactionsContributionsToFoundation" xlink:to="lab_sigi_RelatedPartyTransactionsContributionsToFoundation" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_LandfillSitesRelatedClaimsMember_fa805ddc-66e7-4951-8a82-caa834a26e4d_terseLabel_en-US" xlink:label="lab_sigi_LandfillSitesRelatedClaimsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Landfill Sites Related Claims [Member]</link:label>
    <link:label id="lab_sigi_LandfillSitesRelatedClaimsMember_label_en-US" xlink:label="lab_sigi_LandfillSitesRelatedClaimsMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Landfill Sites Related Claims [Member]</link:label>
    <link:label id="lab_sigi_LandfillSitesRelatedClaimsMember_documentation_en-US" xlink:label="lab_sigi_LandfillSitesRelatedClaimsMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Represents claims related to landfill sites.</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_LandfillSitesRelatedClaimsMember" xlink:to="lab_sigi_LandfillSitesRelatedClaimsMember" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_AllowanceForUncollectiblePremiumsReceivableTable_fd5010f8-69d0-4c89-977a-c86e37f2958e_terseLabel_en-US" xlink:label="lab_sigi_AllowanceForUncollectiblePremiumsReceivableTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Allowance for Uncollectible Premiums Receivable [Table]</link:label>
    <link:label id="lab_sigi_AllowanceForUncollectiblePremiumsReceivableTable_label_en-US" xlink:label="lab_sigi_AllowanceForUncollectiblePremiumsReceivableTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Allowance for Uncollectible Premiums Receivable [Table]</link:label>
    <link:label id="lab_sigi_AllowanceForUncollectiblePremiumsReceivableTable_documentation_en-US" xlink:label="lab_sigi_AllowanceForUncollectiblePremiumsReceivableTable" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Allowance for Uncollectible Premiums Receivable [Table]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_AllowanceForUncollectiblePremiumsReceivableTable" xlink:href="sigi-20211231.xsd#sigi_AllowanceForUncollectiblePremiumsReceivableTable"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_AllowanceForUncollectiblePremiumsReceivableTable" xlink:to="lab_sigi_AllowanceForUncollectiblePremiumsReceivableTable" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_TotalLeasesDueInFiveYears_d60a5970-25a5-40e6-a7a9-88fb3a7f8c9c_terseLabel_en-US" xlink:label="lab_sigi_TotalLeasesDueInFiveYears" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Total Lease Liability, Due Year Five</link:label>
    <link:label id="lab_sigi_TotalLeasesDueInFiveYears_label_en-US" xlink:label="lab_sigi_TotalLeasesDueInFiveYears" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Total Leases Due In Five Years</link:label>
    <link:label id="lab_sigi_TotalLeasesDueInFiveYears_documentation_en-US" xlink:label="lab_sigi_TotalLeasesDueInFiveYears" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Amount of lessee's undiscounted obligation for lease payments for finance and operating leases, due in the fifth fiscal year following the latest fiscal year for all leases.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_TotalLeasesDueInFiveYears" xlink:href="sigi-20211231.xsd#sigi_TotalLeasesDueInFiveYears"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_TotalLeasesDueInFiveYears" xlink:to="lab_sigi_TotalLeasesDueInFiveYears" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_UnrealizedGainLossonEquitySecuritiesSold_dd746f84-b45a-4422-b56d-3c322b407051_terseLabel_en-US" xlink:label="lab_sigi_UnrealizedGainLossonEquitySecuritiesSold" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Unrealized gains (losses) recognized in income on equity securities that were sold in the respective period</link:label>
    <link:label id="lab_sigi_UnrealizedGainLossonEquitySecuritiesSold_label_en-US" xlink:label="lab_sigi_UnrealizedGainLossonEquitySecuritiesSold" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Unrealized Gain Loss on Equity Securities Sold</link:label>
    <link:label id="lab_sigi_UnrealizedGainLossonEquitySecuritiesSold_documentation_en-US" xlink:label="lab_sigi_UnrealizedGainLossonEquitySecuritiesSold" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">The unrealized gains (losses) on equity securities sold during the period.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_UnrealizedGainLossonEquitySecuritiesSold" xlink:href="sigi-20211231.xsd#sigi_UnrealizedGainLossonEquitySecuritiesSold"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_UnrealizedGainLossonEquitySecuritiesSold" xlink:to="lab_sigi_UnrealizedGainLossonEquitySecuritiesSold" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax_0e8c9a58-ca53-4074-9546-db501be61b0e_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Net realized losses (gains) on disposals and losses on intent-to-sell of AFS securities, Gross</link:label>
    <link:label id="lab_us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax_label_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, before Tax</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax" xlink:to="lab_us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesBeforeTax" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_PrepaidReinsurancePremiums_46b8ce1e-ddf6-414d-a48a-0aac55509bd9_terseLabel_en-US" xlink:label="lab_us-gaap_PrepaidReinsurancePremiums" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Prepaid reinsurance premiums (Note 9)</link:label>
    <link:label id="lab_us-gaap_PrepaidReinsurancePremiums_818817b5-eebd-410b-a5c2-d7c6e46ac9bf_verboseLabel_en-US" xlink:label="lab_us-gaap_PrepaidReinsurancePremiums" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Total prepaid reinsurance premiums</link:label>
    <link:label id="lab_us-gaap_PrepaidReinsurancePremiums_label_en-US" xlink:label="lab_us-gaap_PrepaidReinsurancePremiums" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Prepaid Reinsurance Premiums</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PrepaidReinsurancePremiums" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PrepaidReinsurancePremiums"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PrepaidReinsurancePremiums" xlink:to="lab_us-gaap_PrepaidReinsurancePremiums" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_EquitySecuritiesFvNiCost_9b64c9fd-5a89-405e-a157-7061cbf1acfe_terseLabel_en-US" xlink:label="lab_us-gaap_EquitySecuritiesFvNiCost" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Equity securities, cost</link:label>
    <link:label id="lab_us-gaap_EquitySecuritiesFvNiCost_label_en-US" xlink:label="lab_us-gaap_EquitySecuritiesFvNiCost" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Equity Securities, FV-NI, Cost</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquitySecuritiesFvNiCost" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquitySecuritiesFvNiCost"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EquitySecuritiesFvNiCost" xlink:to="lab_us-gaap_EquitySecuritiesFvNiCost" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_EquityMethodInvestmentNonconsolidatedInvesteeOrGroupOfInvesteesMember_650ff14b-17bf-4d56-a03b-2fa5f7fb0d0b_terseLabel_en-US" xlink:label="lab_us-gaap_EquityMethodInvestmentNonconsolidatedInvesteeOrGroupOfInvesteesMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Equity Method Investment, Nonconsolidated Investee or Group of Investees</link:label>
    <link:label id="lab_us-gaap_EquityMethodInvestmentNonconsolidatedInvesteeOrGroupOfInvesteesMember_label_en-US" xlink:label="lab_us-gaap_EquityMethodInvestmentNonconsolidatedInvesteeOrGroupOfInvesteesMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Equity Method Investment, Nonconsolidated Investee or Group of Investees [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EquityMethodInvestmentNonconsolidatedInvesteeOrGroupOfInvesteesMember" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EquityMethodInvestmentNonconsolidatedInvesteeOrGroupOfInvesteesMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EquityMethodInvestmentNonconsolidatedInvesteeOrGroupOfInvesteesMember" xlink:to="lab_us-gaap_EquityMethodInvestmentNonconsolidatedInvesteeOrGroupOfInvesteesMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FairValueByMeasurementFrequencyAxis_473c740a-bd58-4f9b-ab92-79e1da9f96f0_terseLabel_en-US" xlink:label="lab_us-gaap_FairValueByMeasurementFrequencyAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Measurement Frequency [Axis]</link:label>
    <link:label id="lab_us-gaap_FairValueByMeasurementFrequencyAxis_89bdaa71-9af5-4d49-a8fe-914fc15fa36a_verboseLabel_en-US" xlink:label="lab_us-gaap_FairValueByMeasurementFrequencyAxis" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Measurement Frequency [Axis]</link:label>
    <link:label id="lab_us-gaap_FairValueByMeasurementFrequencyAxis_label_en-US" xlink:label="lab_us-gaap_FairValueByMeasurementFrequencyAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Measurement Frequency [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByMeasurementFrequencyAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueByMeasurementFrequencyAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FairValueByMeasurementFrequencyAxis" xlink:to="lab_us-gaap_FairValueByMeasurementFrequencyAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesNetOfTax_34cb1be0-61ae-42ee-91b5-1bf6ffb7603c_negatedTotalLabel_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesNetOfTax" xlink:role="http://www.xbrl.org/2009/role/negatedTotalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Net realized losses (gains) on disposals and losses on intent-to-sell of AFS securities</link:label>
    <link:label id="lab_us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesNetOfTax_6ae2f20f-76e8-40f7-974a-ea1a2131f9ef_negatedLabel_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesNetOfTax" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Amounts reclassified from AOCI,All other</link:label>
    <link:label id="lab_us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesNetOfTax_label_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesNetOfTax" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Net of Tax</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesNetOfTax" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesNetOfTax"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesNetOfTax" xlink:to="lab_us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIForSaleOfSecuritiesNetOfTax" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LeaseCostTableTextBlock_6b0b2ac9-431c-4376-bd56-11cac95b713f_terseLabel_en-US" xlink:label="lab_us-gaap_LeaseCostTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Components of Lease Expense</link:label>
    <link:label id="lab_us-gaap_LeaseCostTableTextBlock_label_en-US" xlink:label="lab_us-gaap_LeaseCostTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Lease, Cost [Table Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LeaseCostTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LeaseCostTableTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LeaseCostTableTextBlock" xlink:to="lab_us-gaap_LeaseCostTableTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_Totalleaseliability_47f9fd8f-ccb2-40ed-a7a4-9e20c2d5325d_terseLabel_en-US" xlink:label="lab_sigi_Totalleaseliability" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Total lease liability</link:label>
    <link:label id="lab_sigi_Totalleaseliability_label_en-US" xlink:label="lab_sigi_Totalleaseliability" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Total lease liability</link:label>
    <link:label id="lab_sigi_Totalleaseliability_documentation_en-US" xlink:label="lab_sigi_Totalleaseliability" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Present value of lessee's discounted obligation for lease payments from finance and operating leases.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_Totalleaseliability" xlink:href="sigi-20211231.xsd#sigi_Totalleaseliability"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_Totalleaseliability" xlink:to="lab_sigi_Totalleaseliability" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ReinsuranceEffectOnClaimsAndBenefitsIncurredAmountAssumed_431a698a-f590-45a1-b11e-779960a406c1_terseLabel_en-US" xlink:label="lab_us-gaap_ReinsuranceEffectOnClaimsAndBenefitsIncurredAmountAssumed" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Assumed</link:label>
    <link:label id="lab_us-gaap_ReinsuranceEffectOnClaimsAndBenefitsIncurredAmountAssumed_label_en-US" xlink:label="lab_us-gaap_ReinsuranceEffectOnClaimsAndBenefitsIncurredAmountAssumed" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Policyholder Benefits and Claims Incurred, Assumed</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReinsuranceEffectOnClaimsAndBenefitsIncurredAmountAssumed" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ReinsuranceEffectOnClaimsAndBenefitsIncurredAmountAssumed"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ReinsuranceEffectOnClaimsAndBenefitsIncurredAmountAssumed" xlink:to="lab_us-gaap_ReinsuranceEffectOnClaimsAndBenefitsIncurredAmountAssumed" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_RemainingReinsuranceBalances_6be11be4-6bb0-4f94-ae7a-17249ef4ced9_totalLabel_en-US" xlink:label="lab_sigi_RemainingReinsuranceBalances" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Total reinsurance balance</link:label>
    <link:label id="lab_sigi_RemainingReinsuranceBalances_label_en-US" xlink:label="lab_sigi_RemainingReinsuranceBalances" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Remaining Reinsurance Balances</link:label>
    <link:label id="lab_sigi_RemainingReinsuranceBalances_documentation_en-US" xlink:label="lab_sigi_RemainingReinsuranceBalances" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">This element represents the known and estimated amount of reinsurance recoverables and the unexpired portion of premiums ceded on policies in force, less all federal and state pools, as of the balance sheet date.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_RemainingReinsuranceBalances" xlink:href="sigi-20211231.xsd#sigi_RemainingReinsuranceBalances"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_RemainingReinsuranceBalances" xlink:to="lab_sigi_RemainingReinsuranceBalances" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_OtherInvestmentsMember_6e08eed0-e88a-4112-93d4-e250c107a417_verboseLabel_en-US" xlink:label="lab_us-gaap_OtherInvestmentsMember" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Other Investment Portfolio [Member]</link:label>
    <link:label id="lab_us-gaap_OtherInvestmentsMember_c2e52058-54a7-4647-9f82-22a9c748e2d4_terseLabel_en-US" xlink:label="lab_us-gaap_OtherInvestmentsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Other Investments [Member]</link:label>
    <link:label id="lab_us-gaap_OtherInvestmentsMember_label_en-US" xlink:label="lab_us-gaap_OtherInvestmentsMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Other Investments [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherInvestmentsMember" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherInvestmentsMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherInvestmentsMember" xlink:to="lab_us-gaap_OtherInvestmentsMember" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_SupplementalLeaseInformationTableTextBlock_362c59ca-c256-4a1e-aaf3-3a4e987cc7e6_terseLabel_en-US" xlink:label="lab_sigi_SupplementalLeaseInformationTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Supplemental Lease Information</link:label>
    <link:label id="lab_sigi_SupplementalLeaseInformationTableTextBlock_label_en-US" xlink:label="lab_sigi_SupplementalLeaseInformationTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Supplemental Lease Information [Table Text Block]</link:label>
    <link:label id="lab_sigi_SupplementalLeaseInformationTableTextBlock_documentation_en-US" xlink:label="lab_sigi_SupplementalLeaseInformationTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Supplemental information about operating and finance leases, including weighted average remaining lease term and weighted average discount rates.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_SupplementalLeaseInformationTableTextBlock" xlink:href="sigi-20211231.xsd#sigi_SupplementalLeaseInformationTableTextBlock"/>
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    <link:label id="lab_sigi_RemainingUnsecuredReinsuranceMember_a231bc20-1e06-45ab-99b7-f32bde1d2734_terseLabel_en-US" xlink:label="lab_sigi_RemainingUnsecuredReinsuranceMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Remaining Unsecured Reinsurance [Member]</link:label>
    <link:label id="lab_sigi_RemainingUnsecuredReinsuranceMember_label_en-US" xlink:label="lab_sigi_RemainingUnsecuredReinsuranceMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Remaining Unsecured Reinsurance [Member]</link:label>
    <link:label id="lab_sigi_RemainingUnsecuredReinsuranceMember_documentation_en-US" xlink:label="lab_sigi_RemainingUnsecuredReinsuranceMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Represents the net unsecured reinsurance balance less all federal and state pools.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_RemainingUnsecuredReinsuranceMember" xlink:href="sigi-20211231.xsd#sigi_RemainingUnsecuredReinsuranceMember"/>
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    <link:label id="lab_us-gaap_DueToRelatedPartiesCurrent_5b01327d-9130-4094-8cf0-b5f1d5efa86f_terseLabel_en-US" xlink:label="lab_us-gaap_DueToRelatedPartiesCurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Due to Related Parties, Current</link:label>
    <link:label id="lab_us-gaap_DueToRelatedPartiesCurrent_label_en-US" xlink:label="lab_us-gaap_DueToRelatedPartiesCurrent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Due to Related Parties, Current</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DueToRelatedPartiesCurrent" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DueToRelatedPartiesCurrent"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DueToRelatedPartiesCurrent" xlink:to="lab_us-gaap_DueToRelatedPartiesCurrent" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_ScheduleOfAggregatedSummarizedIncomeStatementFinancialInformationForPartnerhipsInOurAlternativeInvestmentPortfolioTableTextBlock_838ae5f5-bb01-43e8-99f3-7ee981600e04_terseLabel_en-US" xlink:label="lab_sigi_ScheduleOfAggregatedSummarizedIncomeStatementFinancialInformationForPartnerhipsInOurAlternativeInvestmentPortfolioTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule of Aggregated Summarized Income Statement Financial Information For Partnerships In Our Alternative Investment Portfolio</link:label>
    <link:label id="lab_sigi_ScheduleOfAggregatedSummarizedIncomeStatementFinancialInformationForPartnerhipsInOurAlternativeInvestmentPortfolioTableTextBlock_label_en-US" xlink:label="lab_sigi_ScheduleOfAggregatedSummarizedIncomeStatementFinancialInformationForPartnerhipsInOurAlternativeInvestmentPortfolioTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule Of Aggregated Summarized Income Statement Financial Information For Partnerhips In Our Alternative Investment Portfolio [Table Text Block]</link:label>
    <link:label id="lab_sigi_ScheduleOfAggregatedSummarizedIncomeStatementFinancialInformationForPartnerhipsInOurAlternativeInvestmentPortfolioTableTextBlock_documentation_en-US" xlink:label="lab_sigi_ScheduleOfAggregatedSummarizedIncomeStatementFinancialInformationForPartnerhipsInOurAlternativeInvestmentPortfolioTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule of aggregate summarized income statement information for alternative investments accounted for by the equity method.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_ScheduleOfAggregatedSummarizedIncomeStatementFinancialInformationForPartnerhipsInOurAlternativeInvestmentPortfolioTableTextBlock" xlink:href="sigi-20211231.xsd#sigi_ScheduleOfAggregatedSummarizedIncomeStatementFinancialInformationForPartnerhipsInOurAlternativeInvestmentPortfolioTableTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_ScheduleOfAggregatedSummarizedIncomeStatementFinancialInformationForPartnerhipsInOurAlternativeInvestmentPortfolioTableTextBlock" xlink:to="lab_sigi_ScheduleOfAggregatedSummarizedIncomeStatementFinancialInformationForPartnerhipsInOurAlternativeInvestmentPortfolioTableTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_FundedStatusOfRetirementIncomePlanAxis_8a223fa4-7336-4628-920d-5d549f87c882_terseLabel_en-US" xlink:label="lab_sigi_FundedStatusOfRetirementIncomePlanAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Funded Status Of Retirement Income Plan [Axis]</link:label>
    <link:label id="lab_sigi_FundedStatusOfRetirementIncomePlanAxis_label_en-US" xlink:label="lab_sigi_FundedStatusOfRetirementIncomePlanAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Funded Status Of Retirement Income Plan [Axis]</link:label>
    <link:label id="lab_sigi_FundedStatusOfRetirementIncomePlanAxis_documentation_en-US" xlink:label="lab_sigi_FundedStatusOfRetirementIncomePlanAxis" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Funded status of Retirement Income Plan [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_FundedStatusOfRetirementIncomePlanAxis" xlink:href="sigi-20211231.xsd#sigi_FundedStatusOfRetirementIncomePlanAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_FundedStatusOfRetirementIncomePlanAxis" xlink:to="lab_sigi_FundedStatusOfRetirementIncomePlanAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_LongTermDebtExcludingDebtDiscountAndDebtIssuanceCosts_e6b08769-93a1-47d1-8f0a-a8629863b42e_verboseLabel_en-US" xlink:label="lab_sigi_LongTermDebtExcludingDebtDiscountAndDebtIssuanceCosts" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Long-term Debt</link:label>
    <link:label id="lab_sigi_LongTermDebtExcludingDebtDiscountAndDebtIssuanceCosts_label_en-US" xlink:label="lab_sigi_LongTermDebtExcludingDebtDiscountAndDebtIssuanceCosts" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Long Term Debt Excluding Debt Discount And Debt Issuance Costs</link:label>
    <link:label id="lab_sigi_LongTermDebtExcludingDebtDiscountAndDebtIssuanceCosts_documentation_en-US" xlink:label="lab_sigi_LongTermDebtExcludingDebtDiscountAndDebtIssuanceCosts" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Long Term Debt Excluding Debt Discount And Debt Issuance Costs</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_LongTermDebtExcludingDebtDiscountAndDebtIssuanceCosts" xlink:href="sigi-20211231.xsd#sigi_LongTermDebtExcludingDebtDiscountAndDebtIssuanceCosts"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_LongTermDebtExcludingDebtDiscountAndDebtIssuanceCosts" xlink:to="lab_sigi_LongTermDebtExcludingDebtDiscountAndDebtIssuanceCosts" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_InvestmentPolicyTextBlock_639f5d2a-3c3d-4c85-aa53-b413e6973a91_terseLabel_en-US" xlink:label="lab_us-gaap_InvestmentPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Investments</link:label>
    <link:label id="lab_us-gaap_InvestmentPolicyTextBlock_label_en-US" xlink:label="lab_us-gaap_InvestmentPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Investment, Policy [Policy Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentPolicyTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InvestmentPolicyTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_InvestmentPolicyTextBlock" xlink:to="lab_us-gaap_InvestmentPolicyTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_UnrealizedGainLossOnInvestments_e830f990-6eec-4723-a27b-1e98cd28d2f4_terseLabel_en-US" xlink:label="lab_us-gaap_UnrealizedGainLossOnInvestments" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Unrealized Gain (Loss) on Investments recognized in income on equity securities remaining in our portfolio at end of period</link:label>
    <link:label id="lab_us-gaap_UnrealizedGainLossOnInvestments_label_en-US" xlink:label="lab_us-gaap_UnrealizedGainLossOnInvestments" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Unrealized Gain (Loss) on Investments</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_UnrealizedGainLossOnInvestments" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_UnrealizedGainLossOnInvestments"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_UnrealizedGainLossOnInvestments" xlink:to="lab_us-gaap_UnrealizedGainLossOnInvestments" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_NetCashProvidedByUsedInFinancingActivities_b319c85d-132a-468a-82c7-5fe59c2df7e6_totalLabel_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Net cash (used in) provided by financing activities</link:label>
    <link:label id="lab_us-gaap_NetCashProvidedByUsedInFinancingActivities_label_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Net Cash Provided by (Used in) Financing Activities</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivities"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:to="lab_us-gaap_NetCashProvidedByUsedInFinancingActivities" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_EquityOwnershipPercentageOfSonOfDirectorOfParent_fdd84403-424f-4294-a773-0fccffa42a24_terseLabel_en-US" xlink:label="lab_sigi_EquityOwnershipPercentageOfSonOfDirectorOfParent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Equity Ownership Percentage Of Son Of Director Of Parent</link:label>
    <link:label id="lab_sigi_EquityOwnershipPercentageOfSonOfDirectorOfParent_label_en-US" xlink:label="lab_sigi_EquityOwnershipPercentageOfSonOfDirectorOfParent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Equity Ownership Percentage Of Son Of Director Of Parent</link:label>
    <link:label id="lab_sigi_EquityOwnershipPercentageOfSonOfDirectorOfParent_documentation_en-US" xlink:label="lab_sigi_EquityOwnershipPercentageOfSonOfDirectorOfParent" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">The minimum percentage of the equity of an independent insurance agency owned by a son of a director of the Parent.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_EquityOwnershipPercentageOfSonOfDirectorOfParent" xlink:href="sigi-20211231.xsd#sigi_EquityOwnershipPercentageOfSonOfDirectorOfParent"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_EquityOwnershipPercentageOfSonOfDirectorOfParent" xlink:to="lab_sigi_EquityOwnershipPercentageOfSonOfDirectorOfParent" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ReinsuranceRecoverableCreditQualityIndicatorDateUpdated_6aaf91f2-56f3-4ebb-85ce-589d17506d61_terseLabel_en-US" xlink:label="lab_us-gaap_ReinsuranceRecoverableCreditQualityIndicatorDateUpdated" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Reinsurance Recoverable, Credit Quality Indicator, Date Updated</link:label>
    <link:label id="lab_us-gaap_ReinsuranceRecoverableCreditQualityIndicatorDateUpdated_label_en-US" xlink:label="lab_us-gaap_ReinsuranceRecoverableCreditQualityIndicatorDateUpdated" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Reinsurance Recoverable, Credit Quality Indicator, Date Updated</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReinsuranceRecoverableCreditQualityIndicatorDateUpdated" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ReinsuranceRecoverableCreditQualityIndicatorDateUpdated"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ReinsuranceRecoverableCreditQualityIndicatorDateUpdated" xlink:to="lab_us-gaap_ReinsuranceRecoverableCreditQualityIndicatorDateUpdated" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_TreasuryStockValue_1641f5ff-282d-4b5f-ab66-b4b6afa70b61_negatedLabel_en-US" xlink:label="lab_us-gaap_TreasuryStockValue" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Treasury Stock, at cost</link:label>
    <link:label id="lab_us-gaap_TreasuryStockValue_label_en-US" xlink:label="lab_us-gaap_TreasuryStockValue" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Treasury Stock, Value</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_TreasuryStockValue" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_TreasuryStockValue"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_TreasuryStockValue" xlink:to="lab_us-gaap_TreasuryStockValue" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_PreferredStockRedeemableDomain_81b3b296-4515-4fb3-9746-0c003502aa23_terseLabel_en-US" xlink:label="lab_sigi_PreferredStockRedeemableDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Preferred Stock Redeemable [Domain]</link:label>
    <link:label id="lab_sigi_PreferredStockRedeemableDomain_label_en-US" xlink:label="lab_sigi_PreferredStockRedeemableDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Preferred Stock Redeemable [Domain]</link:label>
    <link:label id="lab_sigi_PreferredStockRedeemableDomain_documentation_en-US" xlink:label="lab_sigi_PreferredStockRedeemableDomain" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Preferred Stock Redeemable</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_PreferredStockRedeemableDomain" xlink:href="sigi-20211231.xsd#sigi_PreferredStockRedeemableDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_PreferredStockRedeemableDomain" xlink:to="lab_sigi_PreferredStockRedeemableDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_CededPremiumsWritten_2dfcc2e0-0bea-454e-824a-853f4752d328_negatedLabel_en-US" xlink:label="lab_us-gaap_CededPremiumsWritten" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Ceded premiums written</link:label>
    <link:label id="lab_us-gaap_CededPremiumsWritten_label_en-US" xlink:label="lab_us-gaap_CededPremiumsWritten" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Ceded Premiums Written</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CededPremiumsWritten" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CededPremiumsWritten"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CededPremiumsWritten" xlink:to="lab_us-gaap_CededPremiumsWritten" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_MiscellaneousIncomeMember_8d21a041-cf2c-4729-b3b9-b3307f793d83_terseLabel_en-US" xlink:label="lab_sigi_MiscellaneousIncomeMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Miscellaneous Income [Member]</link:label>
    <link:label id="lab_sigi_MiscellaneousIncomeMember_label_en-US" xlink:label="lab_sigi_MiscellaneousIncomeMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Miscellaneous Income [Member]</link:label>
    <link:label id="lab_sigi_MiscellaneousIncomeMember_documentation_en-US" xlink:label="lab_sigi_MiscellaneousIncomeMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Reflects the sum of all insurance related revenue, outside of net premiums earned, in the period not otherwise specified.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_MiscellaneousIncomeMember" xlink:href="sigi-20211231.xsd#sigi_MiscellaneousIncomeMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_MiscellaneousIncomeMember" xlink:to="lab_sigi_MiscellaneousIncomeMember" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_RemainingAccrualAxis_c1ab3b08-3755-42e4-8062-95582b7ad1db_terseLabel_en-US" xlink:label="lab_sigi_RemainingAccrualAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Remaining Accrual [Axis]</link:label>
    <link:label id="lab_sigi_RemainingAccrualAxis_label_en-US" xlink:label="lab_sigi_RemainingAccrualAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Remaining Accrual [Axis]</link:label>
    <link:label id="lab_sigi_RemainingAccrualAxis_documentation_en-US" xlink:label="lab_sigi_RemainingAccrualAxis" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Remaining Accrual</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_RemainingAccrualAxis" xlink:href="sigi-20211231.xsd#sigi_RemainingAccrualAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_RemainingAccrualAxis" xlink:to="lab_sigi_RemainingAccrualAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_OtherCostAndExpenseOperating_d2acbcb9-c319-4862-8098-00eae2fb7f20_verboseLabel_en-US" xlink:label="lab_us-gaap_OtherCostAndExpenseOperating" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Other expenses</link:label>
    <link:label id="lab_us-gaap_OtherCostAndExpenseOperating_label_en-US" xlink:label="lab_us-gaap_OtherCostAndExpenseOperating" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Other Cost and Expense, Operating</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherCostAndExpenseOperating" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherCostAndExpenseOperating"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherCostAndExpenseOperating" xlink:to="lab_us-gaap_OtherCostAndExpenseOperating" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_ScheduleofShareBasedCompensationESPPandASPPSharesGrantedTable_cc5588ca-831c-4bf4-9d94-fd9179fbfedc_terseLabel_en-US" xlink:label="lab_sigi_ScheduleofShareBasedCompensationESPPandASPPSharesGrantedTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule of Share-Based Compensation ESPP and ASPP Shares Granted [Table]</link:label>
    <link:label id="lab_sigi_ScheduleofShareBasedCompensationESPPandASPPSharesGrantedTable_label_en-US" xlink:label="lab_sigi_ScheduleofShareBasedCompensationESPPandASPPSharesGrantedTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule of Share-Based Compensation ESPP and ASPP Shares Granted [Table]</link:label>
    <link:label id="lab_sigi_ScheduleofShareBasedCompensationESPPandASPPSharesGrantedTable_documentation_en-US" xlink:label="lab_sigi_ScheduleofShareBasedCompensationESPPandASPPSharesGrantedTable" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Tabular disclosure of schedule of Share-Based Compensation ESPP and ASPP Shares Granted</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_ScheduleofShareBasedCompensationESPPandASPPSharesGrantedTable" xlink:href="sigi-20211231.xsd#sigi_ScheduleofShareBasedCompensationESPPandASPPSharesGrantedTable"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_ScheduleofShareBasedCompensationESPPandASPPSharesGrantedTable" xlink:to="lab_sigi_ScheduleofShareBasedCompensationESPPandASPPSharesGrantedTable" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ScheduleOfSharebasedCompensationRestrictedStockAndRestrictedStockUnitsActivityTableTextBlock_0691f802-ac40-4001-87d6-9bcfb3120c6a_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfSharebasedCompensationRestrictedStockAndRestrictedStockUnitsActivityTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule of Summary of Restricted Stock Units Transactions under Share-Based Payment Plans</link:label>
    <link:label id="lab_us-gaap_ScheduleOfSharebasedCompensationRestrictedStockAndRestrictedStockUnitsActivityTableTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfSharebasedCompensationRestrictedStockAndRestrictedStockUnitsActivityTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Share-based Payment Arrangement, Restricted Stock and Restricted Stock Unit, Activity [Table Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfSharebasedCompensationRestrictedStockAndRestrictedStockUnitsActivityTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfSharebasedCompensationRestrictedStockAndRestrictedStockUnitsActivityTableTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfSharebasedCompensationRestrictedStockAndRestrictedStockUnitsActivityTableTextBlock" xlink:to="lab_us-gaap_ScheduleOfSharebasedCompensationRestrictedStockAndRestrictedStockUnitsActivityTableTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_PremiumTransactionTypeAxis_c5c5f730-80d9-4492-b2f6-a60246021758_terseLabel_en-US" xlink:label="lab_sigi_PremiumTransactionTypeAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Premium Transaction Type [Axis]</link:label>
    <link:label id="lab_sigi_PremiumTransactionTypeAxis_label_en-US" xlink:label="lab_sigi_PremiumTransactionTypeAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Premium Transaction Type [Axis]</link:label>
    <link:label id="lab_sigi_PremiumTransactionTypeAxis_documentation_en-US" xlink:label="lab_sigi_PremiumTransactionTypeAxis" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Premium Transaction Type [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_PremiumTransactionTypeAxis" xlink:href="sigi-20211231.xsd#sigi_PremiumTransactionTypeAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_PremiumTransactionTypeAxis" xlink:to="lab_sigi_PremiumTransactionTypeAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_AMBestRatedReinsurerMember_5070b7e4-ce8a-4651-bf9c-9fe4566044b5_terseLabel_en-US" xlink:label="lab_sigi_AMBestRatedReinsurerMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">AM Best Rated Reinsurer [Member]</link:label>
    <link:label id="lab_sigi_AMBestRatedReinsurerMember_label_en-US" xlink:label="lab_sigi_AMBestRatedReinsurerMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">AM Best Rated Reinsurer [Member]</link:label>
    <link:label id="lab_sigi_AMBestRatedReinsurerMember_documentation_en-US" xlink:label="lab_sigi_AMBestRatedReinsurerMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Total of all rated reinsurer's by credit quality with ratings by AM Best.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_AMBestRatedReinsurerMember" xlink:href="sigi-20211231.xsd#sigi_AMBestRatedReinsurerMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_AMBestRatedReinsurerMember" xlink:to="lab_sigi_AMBestRatedReinsurerMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FairValueDisclosuresTextBlock_a9a1a57d-2f5f-4c63-9ac0-9d2a192e2bd6_terseLabel_en-US" xlink:label="lab_us-gaap_FairValueDisclosuresTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Fair Value Measurements</link:label>
    <link:label id="lab_us-gaap_FairValueDisclosuresTextBlock_label_en-US" xlink:label="lab_us-gaap_FairValueDisclosuresTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Fair Value Disclosures [Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueDisclosuresTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueDisclosuresTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FairValueDisclosuresTextBlock" xlink:to="lab_us-gaap_FairValueDisclosuresTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_PremiumTransactionTypeDomain_4be1c461-99c4-49a8-9667-598bab6fc48f_terseLabel_en-US" xlink:label="lab_sigi_PremiumTransactionTypeDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Premium Transaction Type [Domain]</link:label>
    <link:label id="lab_sigi_PremiumTransactionTypeDomain_label_en-US" xlink:label="lab_sigi_PremiumTransactionTypeDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Premium Transaction Type [Domain]</link:label>
    <link:label id="lab_sigi_PremiumTransactionTypeDomain_documentation_en-US" xlink:label="lab_sigi_PremiumTransactionTypeDomain" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Premium Transaction Type</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_PremiumTransactionTypeDomain" xlink:href="sigi-20211231.xsd#sigi_PremiumTransactionTypeDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_PremiumTransactionTypeDomain" xlink:to="lab_sigi_PremiumTransactionTypeDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_DisclosureofRetiredPlansAbstract_1666fd4e-b86f-4047-8629-68c4599187f5_terseLabel_en-US" xlink:label="lab_sigi_DisclosureofRetiredPlansAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Disclosure of Retired Plans [Abstract]</link:label>
    <link:label id="lab_sigi_DisclosureofRetiredPlansAbstract_label_en-US" xlink:label="lab_sigi_DisclosureofRetiredPlansAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Disclosure of Retired Plans [Abstract]</link:label>
    <link:label id="lab_sigi_DisclosureofRetiredPlansAbstract_documentation_en-US" xlink:label="lab_sigi_DisclosureofRetiredPlansAbstract" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Disclosure of Retired Plans [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_DisclosureofRetiredPlansAbstract" xlink:href="sigi-20211231.xsd#sigi_DisclosureofRetiredPlansAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_DisclosureofRetiredPlansAbstract" xlink:to="lab_sigi_DisclosureofRetiredPlansAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterTenYearsFairValue_f7fd8d88-ed5d-4acb-829e-89fa25099229_terseLabel_en-US" xlink:label="lab_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterTenYearsFairValue" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">HTM due after 10 years fair value</link:label>
    <link:label id="lab_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterTenYearsFairValue_label_en-US" xlink:label="lab_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterTenYearsFairValue" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Debt Securities, Held-to-Maturity, Fair Value, Maturity, Allocated and Single Maturity Date, after Year 10</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterTenYearsFairValue" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterTenYearsFairValue"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterTenYearsFairValue" xlink:to="lab_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterTenYearsFairValue" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_ChangeinHistoricalClaimRateExperienceMember_2a288051-0ffd-4acb-9468-3c6b65a9425d_terseLabel_en-US" xlink:label="lab_sigi_ChangeinHistoricalClaimRateExperienceMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Favorable or unfavorable loss development [Member]</link:label>
    <link:label id="lab_sigi_ChangeinHistoricalClaimRateExperienceMember_label_en-US" xlink:label="lab_sigi_ChangeinHistoricalClaimRateExperienceMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Change in Historical Claim Rate Experience [Member]</link:label>
    <link:label id="lab_sigi_ChangeinHistoricalClaimRateExperienceMember_documentation_en-US" xlink:label="lab_sigi_ChangeinHistoricalClaimRateExperienceMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">A noticeable change in the dollar volume of claims, such as a change in the frequency or number of claims, and the severity (dollar amount) of claims, that is deemed less than temporary, such that it influenced the entity to increase or decrease its claims reserves estimates.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_ChangeinHistoricalClaimRateExperienceMember" xlink:href="sigi-20211231.xsd#sigi_ChangeinHistoricalClaimRateExperienceMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_ChangeinHistoricalClaimRateExperienceMember" xlink:to="lab_sigi_ChangeinHistoricalClaimRateExperienceMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AvailableforsaleSecuritiesMember_97fb4a00-410e-4050-abff-bfbc1d932712_terseLabel_en-US" xlink:label="lab_us-gaap_AvailableforsaleSecuritiesMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Available-for-sale Securities [Member]</link:label>
    <link:label id="lab_us-gaap_AvailableforsaleSecuritiesMember_040c497d-6c07-4dfe-b6b0-268e7e3c58ad_verboseLabel_en-US" xlink:label="lab_us-gaap_AvailableforsaleSecuritiesMember" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Available-for-sale Securities [Member]</link:label>
    <link:label id="lab_us-gaap_AvailableforsaleSecuritiesMember_label_en-US" xlink:label="lab_us-gaap_AvailableforsaleSecuritiesMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Available-for-sale Securities [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AvailableforsaleSecuritiesMember" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AvailableforsaleSecuritiesMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AvailableforsaleSecuritiesMember" xlink:to="lab_us-gaap_AvailableforsaleSecuritiesMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DebtSecuritiesHeldToMaturityAmortizedCostAfterAllowanceForCreditLoss_bfc60d0a-314c-4f44-90df-349b366b5d56_terseLabel_en-US" xlink:label="lab_us-gaap_DebtSecuritiesHeldToMaturityAmortizedCostAfterAllowanceForCreditLoss" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss</link:label>
    <link:label id="lab_us-gaap_DebtSecuritiesHeldToMaturityAmortizedCostAfterAllowanceForCreditLoss_7b5ccfb7-f4c5-470f-9447-64c58e98e914_totalLabel_en-US" xlink:label="lab_us-gaap_DebtSecuritiesHeldToMaturityAmortizedCostAfterAllowanceForCreditLoss" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Total HTM fixed income securities carrying value</link:label>
    <link:label id="lab_us-gaap_DebtSecuritiesHeldToMaturityAmortizedCostAfterAllowanceForCreditLoss_label_en-US" xlink:label="lab_us-gaap_DebtSecuritiesHeldToMaturityAmortizedCostAfterAllowanceForCreditLoss" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesHeldToMaturityAmortizedCostAfterAllowanceForCreditLoss" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtSecuritiesHeldToMaturityAmortizedCostAfterAllowanceForCreditLoss"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DebtSecuritiesHeldToMaturityAmortizedCostAfterAllowanceForCreditLoss" xlink:to="lab_us-gaap_DebtSecuritiesHeldToMaturityAmortizedCostAfterAllowanceForCreditLoss" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RelatedPartyTransactionOtherRevenuesFromTransactionsWithRelatedParty_bc5b7463-420a-4dfa-8e81-d9c2cbc707e0_verboseLabel_en-US" xlink:label="lab_us-gaap_RelatedPartyTransactionOtherRevenuesFromTransactionsWithRelatedParty" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Net realized and unrealized gain (loss)</link:label>
    <link:label id="lab_us-gaap_RelatedPartyTransactionOtherRevenuesFromTransactionsWithRelatedParty_label_en-US" xlink:label="lab_us-gaap_RelatedPartyTransactionOtherRevenuesFromTransactionsWithRelatedParty" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Related Party Transaction, Other Revenues from Transactions with Related Party</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RelatedPartyTransactionOtherRevenuesFromTransactionsWithRelatedParty" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RelatedPartyTransactionOtherRevenuesFromTransactionsWithRelatedParty"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RelatedPartyTransactionOtherRevenuesFromTransactionsWithRelatedParty" xlink:to="lab_us-gaap_RelatedPartyTransactionOtherRevenuesFromTransactionsWithRelatedParty" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RevenuesAbstract_651b255f-4b99-4fc2-9ef8-765fe4f3dbcd_terseLabel_en-US" xlink:label="lab_us-gaap_RevenuesAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Revenues:</link:label>
    <link:label id="lab_us-gaap_RevenuesAbstract_label_en-US" xlink:label="lab_us-gaap_RevenuesAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Revenues [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RevenuesAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RevenuesAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RevenuesAbstract" xlink:to="lab_us-gaap_RevenuesAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_FivePointThreeHundredSeventyFiveMember_4f5675a4-70a4-4de0-9a5c-9bce7ec6cd2b_terseLabel_en-US" xlink:label="lab_sigi_FivePointThreeHundredSeventyFiveMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Five Point Three Hundred Seventy Five Percent Senior Notes [Member]</link:label>
    <link:label id="lab_sigi_FivePointThreeHundredSeventyFiveMember_label_en-US" xlink:label="lab_sigi_FivePointThreeHundredSeventyFiveMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Five Point Three Hundred Seventy Five [Member]</link:label>
    <link:label id="lab_sigi_FivePointThreeHundredSeventyFiveMember_documentation_en-US" xlink:label="lab_sigi_FivePointThreeHundredSeventyFiveMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">This item represents the 5.375% Senior Notes of the company due 2049.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_FivePointThreeHundredSeventyFiveMember" xlink:href="sigi-20211231.xsd#sigi_FivePointThreeHundredSeventyFiveMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_FivePointThreeHundredSeventyFiveMember" xlink:to="lab_sigi_FivePointThreeHundredSeventyFiveMember" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_SixPointSeventyPercentSeniorNotesMember_ad40ba44-5eaa-42ad-8730-33c86eac28aa_terseLabel_en-US" xlink:label="lab_sigi_SixPointSeventyPercentSeniorNotesMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Six Point Seventy Percent Senior Notes [Member]</link:label>
    <link:label id="lab_sigi_SixPointSeventyPercentSeniorNotesMember_3b7bf8cd-0dc9-4f2b-a946-4e62c789343a_verboseLabel_en-US" xlink:label="lab_sigi_SixPointSeventyPercentSeniorNotesMember" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Six Point Seventy Percent Senior Notes due 2035 [Member]</link:label>
    <link:label id="lab_sigi_SixPointSeventyPercentSeniorNotesMember_label_en-US" xlink:label="lab_sigi_SixPointSeventyPercentSeniorNotesMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Six Point Seventy Percent Senior Notes [Member]</link:label>
    <link:label id="lab_sigi_SixPointSeventyPercentSeniorNotesMember_documentation_en-US" xlink:label="lab_sigi_SixPointSeventyPercentSeniorNotesMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">This item represents the 6.70% Senior Notes of the company due 2035.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_SixPointSeventyPercentSeniorNotesMember" xlink:href="sigi-20211231.xsd#sigi_SixPointSeventyPercentSeniorNotesMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_SixPointSeventyPercentSeniorNotesMember" xlink:to="lab_sigi_SixPointSeventyPercentSeniorNotesMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_GoodwillAndIntangibleAssetsGoodwillPolicy_1ace246b-b413-4fac-ba0b-6c285bb0869a_terseLabel_en-US" xlink:label="lab_us-gaap_GoodwillAndIntangibleAssetsGoodwillPolicy" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Goodwill</link:label>
    <link:label id="lab_us-gaap_GoodwillAndIntangibleAssetsGoodwillPolicy_label_en-US" xlink:label="lab_us-gaap_GoodwillAndIntangibleAssetsGoodwillPolicy" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Goodwill and Intangible Assets, Goodwill, Policy [Policy Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_GoodwillAndIntangibleAssetsGoodwillPolicy" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_GoodwillAndIntangibleAssetsGoodwillPolicy"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_GoodwillAndIntangibleAssetsGoodwillPolicy" xlink:to="lab_us-gaap_GoodwillAndIntangibleAssetsGoodwillPolicy" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ComputerSoftwareIntangibleAssetMember_17620883-f906-4ae7-a383-dec5b14a8645_terseLabel_en-US" xlink:label="lab_us-gaap_ComputerSoftwareIntangibleAssetMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Computer software [Member]</link:label>
    <link:label id="lab_us-gaap_ComputerSoftwareIntangibleAssetMember_label_en-US" xlink:label="lab_us-gaap_ComputerSoftwareIntangibleAssetMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Computer Software, Intangible Asset [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ComputerSoftwareIntangibleAssetMember" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ComputerSoftwareIntangibleAssetMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ComputerSoftwareIntangibleAssetMember" xlink:to="lab_us-gaap_ComputerSoftwareIntangibleAssetMember" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_DocumentPeriodEndDate_b9522fae-5ceb-49af-84ae-ed5ae40e0062_terseLabel_en-US" xlink:label="lab_dei_DocumentPeriodEndDate" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Document Period End Date</link:label>
    <link:label id="lab_dei_DocumentPeriodEndDate_label_en-US" xlink:label="lab_dei_DocumentPeriodEndDate" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Document Period End Date</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentPeriodEndDate" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_DocumentPeriodEndDate"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_DocumentPeriodEndDate" xlink:to="lab_dei_DocumentPeriodEndDate" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_PaymentsToAcquireAdditionalInterestInSubsidiaries_4b531681-43bd-4785-93e3-1dfe2d76fb72_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_PaymentsToAcquireAdditionalInterestInSubsidiaries" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Capital contribution to subsidiaries</link:label>
    <link:label id="lab_us-gaap_PaymentsToAcquireAdditionalInterestInSubsidiaries_label_en-US" xlink:label="lab_us-gaap_PaymentsToAcquireAdditionalInterestInSubsidiaries" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Payments to Acquire Additional Interest in Subsidiaries</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquireAdditionalInterestInSubsidiaries" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PaymentsToAcquireAdditionalInterestInSubsidiaries"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PaymentsToAcquireAdditionalInterestInSubsidiaries" xlink:to="lab_us-gaap_PaymentsToAcquireAdditionalInterestInSubsidiaries" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_FederalHomeLoanBankAdvancesBranchOfFHLBBankStateDomain_7a7638ce-0046-408a-bdff-2e8dc41eb6f1_terseLabel_en-US" xlink:label="lab_srt_FederalHomeLoanBankAdvancesBranchOfFHLBBankStateDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Federal Home Loan Bank Branch [Domain]</link:label>
    <link:label id="lab_srt_FederalHomeLoanBankAdvancesBranchOfFHLBBankStateDomain_label_en-US" xlink:label="lab_srt_FederalHomeLoanBankAdvancesBranchOfFHLBBankStateDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Federal Home Loan Bank Branch [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_FederalHomeLoanBankAdvancesBranchOfFHLBBankStateDomain" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_FederalHomeLoanBankAdvancesBranchOfFHLBBankStateDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_FederalHomeLoanBankAdvancesBranchOfFHLBBankStateDomain" xlink:to="lab_srt_FederalHomeLoanBankAdvancesBranchOfFHLBBankStateDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_FinanceLeaseExpense_60bf9767-e8b1-4cea-b5f4-1eb2c52d4c02_terseLabel_en-US" xlink:label="lab_sigi_FinanceLeaseExpense" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Total finance lease cost</link:label>
    <link:label id="lab_sigi_FinanceLeaseExpense_label_en-US" xlink:label="lab_sigi_FinanceLeaseExpense" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Finance Lease Expense</link:label>
    <link:label id="lab_sigi_FinanceLeaseExpense_documentation_en-US" xlink:label="lab_sigi_FinanceLeaseExpense" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Total finance lease expense, comprised of amortization expense on the right-of-use asset and interest expense.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_FinanceLeaseExpense" xlink:href="sigi-20211231.xsd#sigi_FinanceLeaseExpense"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_FinanceLeaseExpense" xlink:to="lab_sigi_FinanceLeaseExpense" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FixedIncomeSecuritiesMember_b7c274fa-da78-4d3b-810e-299041c96529_terseLabel_en-US" xlink:label="lab_us-gaap_FixedIncomeSecuritiesMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Fixed Income Securities [Member]</link:label>
    <link:label id="lab_us-gaap_FixedIncomeSecuritiesMember_label_en-US" xlink:label="lab_us-gaap_FixedIncomeSecuritiesMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Fixed Income Securities [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FixedIncomeSecuritiesMember" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FixedIncomeSecuritiesMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FixedIncomeSecuritiesMember" xlink:to="lab_us-gaap_FixedIncomeSecuritiesMember" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_OtherPersonalMember_68e5f3ac-da3a-4c7b-bbd1-7334c300e541_terseLabel_en-US" xlink:label="lab_sigi_OtherPersonalMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Other Personal [Member]</link:label>
    <link:label id="lab_sigi_OtherPersonalMember_label_en-US" xlink:label="lab_sigi_OtherPersonalMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Other Personal [Member]</link:label>
    <link:label id="lab_sigi_OtherPersonalMember_documentation_en-US" xlink:label="lab_sigi_OtherPersonalMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Represents insurance coverage provided to policy holders on other personal line policies.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_OtherPersonalMember" xlink:href="sigi-20211231.xsd#sigi_OtherPersonalMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_OtherPersonalMember" xlink:to="lab_sigi_OtherPersonalMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_PolicyholderBenefitsAndClaimsIncurredGross_8295ee11-900a-46b0-bad8-8ffac6ab095b_terseLabel_en-US" xlink:label="lab_us-gaap_PolicyholderBenefitsAndClaimsIncurredGross" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Direct</link:label>
    <link:label id="lab_us-gaap_PolicyholderBenefitsAndClaimsIncurredGross_label_en-US" xlink:label="lab_us-gaap_PolicyholderBenefitsAndClaimsIncurredGross" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Policyholder Benefits and Claims Incurred, Direct</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PolicyholderBenefitsAndClaimsIncurredGross" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PolicyholderBenefitsAndClaimsIncurredGross"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PolicyholderBenefitsAndClaimsIncurredGross" xlink:to="lab_us-gaap_PolicyholderBenefitsAndClaimsIncurredGross" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_ConsolidatedEntitiesDomain_3f671c78-9bc6-4412-a2d8-16b981436217_terseLabel_en-US" xlink:label="lab_srt_ConsolidatedEntitiesDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Consolidated Entities [Domain]</link:label>
    <link:label id="lab_srt_ConsolidatedEntitiesDomain_label_en-US" xlink:label="lab_srt_ConsolidatedEntitiesDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Consolidated Entities [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ConsolidatedEntitiesDomain" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ConsolidatedEntitiesDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_ConsolidatedEntitiesDomain" xlink:to="lab_srt_ConsolidatedEntitiesDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ProceedsFromSaleOfOtherInvestments_8f325054-e6c6-465c-9fe1-23faf274244e_terseLabel_en-US" xlink:label="lab_us-gaap_ProceedsFromSaleOfOtherInvestments" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Proceeds from Sale of Other Investments</link:label>
    <link:label id="lab_us-gaap_ProceedsFromSaleOfOtherInvestments_label_en-US" xlink:label="lab_us-gaap_ProceedsFromSaleOfOtherInvestments" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Proceeds from Sale of Other Investments</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ProceedsFromSaleOfOtherInvestments" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ProceedsFromSaleOfOtherInvestments"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ProceedsFromSaleOfOtherInvestments" xlink:to="lab_us-gaap_ProceedsFromSaleOfOtherInvestments" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_PropertyPlantAndEquipmentTextBlock_6cce0547-4c33-46ef-b516-d0a415570afb_terseLabel_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Estimated Useful Life for Property and Equipment</link:label>
    <link:label id="lab_us-gaap_PropertyPlantAndEquipmentTextBlock_label_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Property, Plant and Equipment [Table Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PropertyPlantAndEquipmentTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentTextBlock" xlink:to="lab_us-gaap_PropertyPlantAndEquipmentTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AccruedInvestmentIncomeReceivable_3cdbdb3b-5817-4bce-973c-5e62ee5563a6_terseLabel_en-US" xlink:label="lab_us-gaap_AccruedInvestmentIncomeReceivable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Accrued investment income</link:label>
    <link:label id="lab_us-gaap_AccruedInvestmentIncomeReceivable_label_en-US" xlink:label="lab_us-gaap_AccruedInvestmentIncomeReceivable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Accrued Investment Income Receivable</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AccruedInvestmentIncomeReceivable" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AccruedInvestmentIncomeReceivable"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AccruedInvestmentIncomeReceivable" xlink:to="lab_us-gaap_AccruedInvestmentIncomeReceivable" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_IncomeStatementLocationDomain_47c7c12b-74ce-4791-ab1c-b3509af920de_terseLabel_en-US" xlink:label="lab_us-gaap_IncomeStatementLocationDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Income Statement Location [Domain]</link:label>
    <link:label id="lab_us-gaap_IncomeStatementLocationDomain_label_en-US" xlink:label="lab_us-gaap_IncomeStatementLocationDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Income Statement Location [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeStatementLocationDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeStatementLocationDomain"/>
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    <link:label id="lab_us-gaap_NoncashOrPartNoncashAcquisitionInvestmentsAcquired1_aa6ca7b7-2733-4e3e-8ab9-2598de7c72cb_terseLabel_en-US" xlink:label="lab_us-gaap_NoncashOrPartNoncashAcquisitionInvestmentsAcquired1" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Corporate actions related to securities</link:label>
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    <link:label id="lab_us-gaap_EquitySecuritiesFvNiUnrealizedGainLoss_e2dec4e0-a37d-40fe-bd41-a9a86518ffff_terseLabel_en-US" xlink:label="lab_us-gaap_EquitySecuritiesFvNiUnrealizedGainLoss" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Net unrealized losses on equity securities</link:label>
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    <link:label id="lab_sigi_CommercialMortgageLoanFairValue_b3cc8c33-66f1-44af-8515-bba83175a376_terseLabel_en-US" xlink:label="lab_sigi_CommercialMortgageLoanFairValue" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Commercial mortgage loan, fair value</link:label>
    <link:label id="lab_sigi_CommercialMortgageLoanFairValue_label_en-US" xlink:label="lab_sigi_CommercialMortgageLoanFairValue" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Commercial mortgage loan, fair value</link:label>
    <link:label id="lab_sigi_CommercialMortgageLoanFairValue_documentation_en-US" xlink:label="lab_sigi_CommercialMortgageLoanFairValue" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Fair value of investment in commercial loan measured at original cost.</link:label>
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    <link:label id="lab_us-gaap_LeasesAbstract_a0097cf6-228c-4c9d-9d67-9ee3da3080a2_terseLabel_en-US" xlink:label="lab_us-gaap_LeasesAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Leases [Abstract]</link:label>
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    <link:label id="lab_us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansAdjustmentBeforeTaxPortionAttributableToParent_b47a3220-b960-4f8d-a7ee-f3137204ed97_totalLabel_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansAdjustmentBeforeTaxPortionAttributableToParent" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Total recognized in other comprehensive income</link:label>
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    <link:label id="lab_us-gaap_IncomeTaxPolicyTextBlock_3dabfe72-ec8c-4c71-9ee1-6876e2db2af8_terseLabel_en-US" xlink:label="lab_us-gaap_IncomeTaxPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Federal Income Tax</link:label>
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    <link:label id="lab_sigi_UnrealizedGainLossonSecuritiesTableTextBlock_80be2add-5bf6-4089-ab35-8f66af94c0cc_terseLabel_en-US" xlink:label="lab_sigi_UnrealizedGainLossonSecuritiesTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Unrealized Gain (Loss) on Equity Securities</link:label>
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    <link:label id="lab_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems_4afb9d93-3921-4402-a6d3-e9c5ecf56caa_terseLabel_en-US" xlink:label="lab_us-gaap_AccumulatedOtherComprehensiveIncomeLossLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Accumulated Other Comprehensive Income (Loss) [Line Items]</link:label>
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    <link:label id="lab_sigi_FundedStatusOfRetirementIncomePlanDomain_2b5a6c93-4c12-4555-bdc6-de60d5e5c1bd_terseLabel_en-US" xlink:label="lab_sigi_FundedStatusOfRetirementIncomePlanDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Funded Status Of Retirement Income Plan [Domain]</link:label>
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    <link:label id="lab_sigi_FundedStatusOfRetirementIncomePlanDomain_documentation_en-US" xlink:label="lab_sigi_FundedStatusOfRetirementIncomePlanDomain" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">[Domain] for Funded status of Retirement Income Plan [Axis]</link:label>
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    <link:label id="lab_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpense_25f8ad39-cf05-4cda-8271-7fceaeae6928_periodStartLabel_en-US" xlink:label="lab_us-gaap_LiabilityForClaimsAndClaimsAdjustmentExpense" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Gross reserve for loss and loss expense, at beginning of year</link:label>
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    <link:label id="lab_dei_EntityAddressPostalZipCode_6e8031f4-afc2-4368-b0b6-131dba3f02fe_terseLabel_en-US" xlink:label="lab_dei_EntityAddressPostalZipCode" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Entity Address, Postal Zip Code</link:label>
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    <link:label id="lab_us-gaap_LongTermDebtPercentageBearingFixedInterestRate_2e723c50-593f-4894-9a76-fcd91dc0af19_terseLabel_en-US" xlink:label="lab_us-gaap_LongTermDebtPercentageBearingFixedInterestRate" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Interest Rate</link:label>
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    <link:label id="lab_us-gaap_SeriesBMember_8aa86bdd-4007-45eb-86f5-238c75ee75a9_terseLabel_en-US" xlink:label="lab_us-gaap_SeriesBMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Series B [Member]</link:label>
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    <link:label id="lab_us-gaap_ConsolidationPolicyTextBlock_37624fc4-7f32-4e98-89ad-4bfe21d32255_terseLabel_en-US" xlink:label="lab_us-gaap_ConsolidationPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Principles of Consolidation</link:label>
    <link:label id="lab_us-gaap_ConsolidationPolicyTextBlock_label_en-US" xlink:label="lab_us-gaap_ConsolidationPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Consolidation, Policy [Policy Text Block]</link:label>
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    <link:label id="lab_dei_EntityShellCompany_e5eb4248-3917-48d8-831c-8c41abd817e4_terseLabel_en-US" xlink:label="lab_dei_EntityShellCompany" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Entity Shell Company</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_EntityShellCompany" xlink:to="lab_dei_EntityShellCompany" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DeferredPolicyAcquisitionCosts_d4c8a9aa-feab-42a3-9abf-ce359e0ba910_terseLabel_en-US" xlink:label="lab_us-gaap_DeferredPolicyAcquisitionCosts" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Deferred policy acquisition costs (Note 2)</link:label>
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    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DeferredPolicyAcquisitionCosts" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DeferredPolicyAcquisitionCosts"/>
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    <link:label id="lab_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1_b3e4270e-fd9d-40fd-9b95-cc4075b569bb_terseLabel_en-US" xlink:label="lab_us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Expected term</link:label>
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    <link:label id="lab_us-gaap_EmployeeStockMember_8410e73f-1c70-4149-97f0-79958f7e99b1_verboseLabel_en-US" xlink:label="lab_us-gaap_EmployeeStockMember" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Employee Stock Purchase Plan [Member]</link:label>
    <link:label id="lab_us-gaap_EmployeeStockMember_label_en-US" xlink:label="lab_us-gaap_EmployeeStockMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Employee Stock [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EmployeeStockMember" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EmployeeStockMember"/>
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    <link:label id="lab_us-gaap_AssumedPremiumsWritten_c039d0a8-ff4b-4167-b354-27cea72ae8dd_terseLabel_en-US" xlink:label="lab_us-gaap_AssumedPremiumsWritten" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Assumed</link:label>
    <link:label id="lab_us-gaap_AssumedPremiumsWritten_label_en-US" xlink:label="lab_us-gaap_AssumedPremiumsWritten" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Assumed Premiums Written</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssumedPremiumsWritten" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AssumedPremiumsWritten"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AssumedPremiumsWritten" xlink:to="lab_us-gaap_AssumedPremiumsWritten" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ReinsuranceEffectOnClaimsAndBenefitsIncurredAmountCeded_0d8b5a2f-9fe3-4530-a055-44870d8d1c78_negatedLabel_en-US" xlink:label="lab_us-gaap_ReinsuranceEffectOnClaimsAndBenefitsIncurredAmountCeded" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Ceded loss and loss expense</link:label>
    <link:label id="lab_us-gaap_ReinsuranceEffectOnClaimsAndBenefitsIncurredAmountCeded_label_en-US" xlink:label="lab_us-gaap_ReinsuranceEffectOnClaimsAndBenefitsIncurredAmountCeded" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Policyholder Benefits and Claims Incurred, Ceded</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReinsuranceEffectOnClaimsAndBenefitsIncurredAmountCeded" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ReinsuranceEffectOnClaimsAndBenefitsIncurredAmountCeded"/>
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    <link:label id="lab_sigi_NetChangeInUnrealizedAppreciationDepreciationOfEquityMethodInvestees_ef3edb31-21b4-43f4-a300-7fb2464eb4ad_terseLabel_en-US" xlink:label="lab_sigi_NetChangeInUnrealizedAppreciationDepreciationOfEquityMethodInvestees" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Net change in unrealized appreciation</link:label>
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    <link:label id="lab_us-gaap_ProceedsFromSaleOfEquitySecuritiesFvNi_0599a0f3-4666-4bd5-a336-7691b8631427_terseLabel_en-US" xlink:label="lab_us-gaap_ProceedsFromSaleOfEquitySecuritiesFvNi" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Sale of equity securities</link:label>
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    <link:label id="lab_dei_CurrentFiscalYearEndDate_9bf9c382-4ff6-4179-a086-2908a8602c2a_terseLabel_en-US" xlink:label="lab_dei_CurrentFiscalYearEndDate" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Current Fiscal Year End Date</link:label>
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    <link:label id="lab_sigi_Netunrealizedgainlossesoninvestmentsecuritiesinothercomprehensiveincomenetofdeferredincometax_8d6c4724-92d4-488c-b349-c029bce0f746_totalLabel_en-US" xlink:label="lab_sigi_Netunrealizedgainlossesoninvestmentsecuritiesinothercomprehensiveincomenetofdeferredincometax" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Net unrealized gains, net of deferred income tax</link:label>
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    <link:label id="lab_us-gaap_OperatingLeaseRightOfUseAssetStatementOfFinancialPositionExtensibleList_label_en-US" xlink:label="lab_us-gaap_OperatingLeaseRightOfUseAssetStatementOfFinancialPositionExtensibleList" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]</link:label>
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    <link:label id="lab_sigi_RealAssetsMember_d5104009-fde9-43e7-a60b-52e0dc8a95e9_terseLabel_en-US" xlink:label="lab_sigi_RealAssetsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Real Assets [Member]</link:label>
    <link:label id="lab_sigi_RealAssetsMember_label_en-US" xlink:label="lab_sigi_RealAssetsMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Real Assets [Member]</link:label>
    <link:label id="lab_sigi_RealAssetsMember_documentation_en-US" xlink:label="lab_sigi_RealAssetsMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">This strategy includes the Energy &amp; Power Generation and Real Estate strategies, making energy and power generation investments in cash flow generating infrastructure assets and investing opportunistically in real estate in North America, Europe, and Asia via direct property ownership, joint ventures, mortgages, and investments in equity and debt instruments.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_RealAssetsMember" xlink:href="sigi-20211231.xsd#sigi_RealAssetsMember"/>
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    <link:label id="lab_us-gaap_OperatingLeaseLiabilityStatementOfFinancialPositionExtensibleList_288164a7-98ee-4f18-be11-eee7092fe505_terseLabel_en-US" xlink:label="lab_us-gaap_OperatingLeaseLiabilityStatementOfFinancialPositionExtensibleList" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Operating Lease, Liability, Statement of Financial Position [Extensible Enumeration]</link:label>
    <link:label id="lab_us-gaap_OperatingLeaseLiabilityStatementOfFinancialPositionExtensibleList_label_en-US" xlink:label="lab_us-gaap_OperatingLeaseLiabilityStatementOfFinancialPositionExtensibleList" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Operating Lease, Liability, Statement of Financial Position [Extensible Enumeration]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeaseLiabilityStatementOfFinancialPositionExtensibleList" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingLeaseLiabilityStatementOfFinancialPositionExtensibleList"/>
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    <link:label id="lab_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract_8b774078-82be-4cf6-aa44-74a9b3e2d14a_terseLabel_en-US" xlink:label="lab_us-gaap_AdjustmentsToReconcileNetIncomeLossToCashProvidedByUsedInOperatingActivitiesAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Adjustments to reconcile net income to net cash provided by (used in) operating activities:</link:label>
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    <link:label id="lab_sigi_NarrativeAbstract_630d5ce5-fa49-4fdd-a4a9-a604c63e9b2f_terseLabel_en-US" xlink:label="lab_sigi_NarrativeAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Narrative [Abstract]</link:label>
    <link:label id="lab_sigi_NarrativeAbstract_label_en-US" xlink:label="lab_sigi_NarrativeAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Narrative [Abstract]</link:label>
    <link:label id="lab_sigi_NarrativeAbstract_documentation_en-US" xlink:label="lab_sigi_NarrativeAbstract" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Narrative [Abstract]</link:label>
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    <link:label id="lab_sigi_PercentHedgeAgainstProjectedBenefitObligation_documentation_en-US" xlink:label="lab_sigi_PercentHedgeAgainstProjectedBenefitObligation" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Percent hedge provided by the liability hedging assets against the projected benefit obligation.</link:label>
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    <link:label id="lab_us-gaap_NoncumulativePreferredStockMember_7e4995f8-0d17-4525-b01a-aab3fadd6310_terseLabel_en-US" xlink:label="lab_us-gaap_NoncumulativePreferredStockMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Depositary Shares [Member]</link:label>
    <link:label id="lab_us-gaap_NoncumulativePreferredStockMember_label_en-US" xlink:label="lab_us-gaap_NoncumulativePreferredStockMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Noncumulative Preferred Stock [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_NoncumulativePreferredStockMember" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_NoncumulativePreferredStockMember"/>
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    <link:label id="lab_us-gaap_ComputerEquipmentMember_00d4c208-c7d9-4079-bf27-24648527a815_terseLabel_en-US" xlink:label="lab_us-gaap_ComputerEquipmentMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Computer hardware [Member]</link:label>
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    <link:label id="lab_us-gaap_RelatedPartyTransactionsDisclosureTextBlock_ef75db5b-fb64-49d7-8465-fd21774a7d0a_terseLabel_en-US" xlink:label="lab_us-gaap_RelatedPartyTransactionsDisclosureTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Related Party Transactions</link:label>
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    <link:label id="lab_us-gaap_StockRepurchaseProgramAuthorizedAmount1_72e7de27-bc6f-4d5c-8632-21150045b972_terseLabel_en-US" xlink:label="lab_us-gaap_StockRepurchaseProgramAuthorizedAmount1" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Stock Repurchase Program, Authorized Amount</link:label>
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    <link:label id="lab_sigi_IntercompanyNotesPayable_35bca89e-8127-40c0-a153-d809ebe5d12b_terseLabel_en-US" xlink:label="lab_sigi_IntercompanyNotesPayable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Intercompany notes payable</link:label>
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    <link:label id="lab_us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate_614076fb-e076-4a7c-ac99-99433ad953b9_terseLabel_en-US" xlink:label="lab_us-gaap_EffectiveIncomeTaxRateReconciliationAtFederalStatutoryIncomeTaxRate" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent</link:label>
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    <link:label id="lab_us-gaap_AssetsAbstract_label_en-US" xlink:label="lab_us-gaap_AssetsAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Assets [Abstract]</link:label>
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    <link:label id="lab_us-gaap_RelatedPartyTransactionsAbstract_fc421131-9dde-4212-a8cc-6af59a3d3ca8_terseLabel_en-US" xlink:label="lab_us-gaap_RelatedPartyTransactionsAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Related Party Transactions [Abstract]</link:label>
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    <link:label id="lab_us-gaap_SubsegmentsAxis_0656c87e-29b9-4325-925f-b54fbb990d3a_terseLabel_en-US" xlink:label="lab_us-gaap_SubsegmentsAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Subsegments [Axis]</link:label>
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    <link:label id="lab_sigi_EquityInUndistributedIncomeOfContinuingSubsidiariesNetOfTax_documentation_en-US" xlink:label="lab_sigi_EquityInUndistributedIncomeOfContinuingSubsidiariesNetOfTax" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">This element represents the parent's equity in undistributed income of its continuing subsidiaries for the period, net of tax.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_EquityInUndistributedIncomeOfContinuingSubsidiariesNetOfTax" xlink:href="sigi-20211231.xsd#sigi_EquityInUndistributedIncomeOfContinuingSubsidiariesNetOfTax"/>
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    <link:label id="lab_sigi_DividendPaidToParentTableTextBlock_7299f677-8aea-46e9-8e40-be0d8e8f58f5_terseLabel_en-US" xlink:label="lab_sigi_DividendPaidToParentTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule of Insurance Subsidiaries Dividend Paid To Parent</link:label>
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    <link:label id="lab_us-gaap_OtherLiabilitiesMember_42ce2550-ac31-49d6-8785-a8e61906137e_terseLabel_en-US" xlink:label="lab_us-gaap_OtherLiabilitiesMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Other Liabilities [Member]</link:label>
    <link:label id="lab_us-gaap_OtherLiabilitiesMember_label_en-US" xlink:label="lab_us-gaap_OtherLiabilitiesMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Other Liabilities [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherLiabilitiesMember" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherLiabilitiesMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherLiabilitiesMember" xlink:to="lab_us-gaap_OtherLiabilitiesMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_CededCreditRiskReinsurerDomain_25f8d2a7-057b-4b14-bc69-928fc689286e_terseLabel_en-US" xlink:label="lab_us-gaap_CededCreditRiskReinsurerDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Ceded Credit Risk, Reinsurer [Domain]</link:label>
    <link:label id="lab_us-gaap_CededCreditRiskReinsurerDomain_label_en-US" xlink:label="lab_us-gaap_CededCreditRiskReinsurerDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Ceded Credit Risk, Reinsurer [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CededCreditRiskReinsurerDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CededCreditRiskReinsurerDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CededCreditRiskReinsurerDomain" xlink:to="lab_us-gaap_CededCreditRiskReinsurerDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RightOfUseAssetObtainedInExchangeForFinanceLeaseLiability_04ee4a80-d9b6-4a63-a13d-897df519692a_terseLabel_en-US" xlink:label="lab_us-gaap_RightOfUseAssetObtainedInExchangeForFinanceLeaseLiability" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Assets acquired under finance lease arrangements</link:label>
    <link:label id="lab_us-gaap_RightOfUseAssetObtainedInExchangeForFinanceLeaseLiability_label_en-US" xlink:label="lab_us-gaap_RightOfUseAssetObtainedInExchangeForFinanceLeaseLiability" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Right-of-Use Asset Obtained in Exchange for Finance Lease Liability</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RightOfUseAssetObtainedInExchangeForFinanceLeaseLiability" xlink:to="lab_us-gaap_RightOfUseAssetObtainedInExchangeForFinanceLeaseLiability" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_USStatesAndPoliticalSubdivisionsMember_86242123-d7b2-44b1-aa6e-cd7c7f472ce0_terseLabel_en-US" xlink:label="lab_us-gaap_USStatesAndPoliticalSubdivisionsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Obligations of States and Political Subdivisions [Member]</link:label>
    <link:label id="lab_us-gaap_USStatesAndPoliticalSubdivisionsMember_label_en-US" xlink:label="lab_us-gaap_USStatesAndPoliticalSubdivisionsMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">US States and Political Subdivisions Debt Securities [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_USStatesAndPoliticalSubdivisionsMember" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_USStatesAndPoliticalSubdivisionsMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_USStatesAndPoliticalSubdivisionsMember" xlink:to="lab_us-gaap_USStatesAndPoliticalSubdivisionsMember" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_PercentageOfUnpaidNfipClaimsCededByFederalGovernment_a2f29fa5-b837-412e-bbde-a2b4cb2210d1_terseLabel_en-US" xlink:label="lab_sigi_PercentageOfUnpaidNfipClaimsCededByFederalGovernment" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Percentage of NFIP claims ceded to the federal government</link:label>
    <link:label id="lab_sigi_PercentageOfUnpaidNfipClaimsCededByFederalGovernment_label_en-US" xlink:label="lab_sigi_PercentageOfUnpaidNfipClaimsCededByFederalGovernment" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Percentage of unpaid NFIP claims ceded by federal government</link:label>
    <link:label id="lab_sigi_PercentageOfUnpaidNfipClaimsCededByFederalGovernment_documentation_en-US" xlink:label="lab_sigi_PercentageOfUnpaidNfipClaimsCededByFederalGovernment" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Percentage of unpaid NFIP claims ceded by federal government</link:label>
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    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod_0b4baf77-485a-4bd3-a642-c881958b0cc3_terseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Granted in 2021, number of shares</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod" xlink:to="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsGrantsInPeriod" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_AMBestBPlusPlusRatingMember_eb541b34-1890-4c7b-aa14-cd0abaf788e3_terseLabel_en-US" xlink:label="lab_srt_AMBestBPlusPlusRatingMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">AM Best, B++ Rating [Member]</link:label>
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    <link:label id="lab_sigi_PaymentsToAcquireCommercialMortgageLoans_f8505457-65ce-40d7-a1e6-ad725ca94c56_terseLabel_en-US" xlink:label="lab_sigi_PaymentsToAcquireCommercialMortgageLoans" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Purchase of commercial mortgage loans</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_PaymentsToAcquireCommercialMortgageLoans" xlink:to="lab_sigi_PaymentsToAcquireCommercialMortgageLoans" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_PropertyPlantAndEquipmentPolicyTextBlock_f07d66cf-9f94-4200-a4b0-1c0f93590264_terseLabel_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Property and Equipment</link:label>
    <link:label id="lab_us-gaap_PropertyPlantAndEquipmentPolicyTextBlock_label_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Property, Plant and Equipment, Policy [Policy Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentPolicyTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PropertyPlantAndEquipmentPolicyTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentPolicyTextBlock" xlink:to="lab_us-gaap_PropertyPlantAndEquipmentPolicyTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ProceedsFromIssuanceOfSharesUnderIncentiveAndShareBasedCompensationPlansIncludingStockOptions_f3138d80-25bc-4929-96bc-a30408f25aa3_terseLabel_en-US" xlink:label="lab_us-gaap_ProceedsFromIssuanceOfSharesUnderIncentiveAndShareBasedCompensationPlansIncludingStockOptions" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Net proceeds from stock purchase and compensation plans</link:label>
    <link:label id="lab_us-gaap_ProceedsFromIssuanceOfSharesUnderIncentiveAndShareBasedCompensationPlansIncludingStockOptions_label_en-US" xlink:label="lab_us-gaap_ProceedsFromIssuanceOfSharesUnderIncentiveAndShareBasedCompensationPlansIncludingStockOptions" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Proceeds, Issuance of Shares, Share-based Payment Arrangement, Including Option Exercised</link:label>
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    <link:label id="lab_us-gaap_PaymentsToAcquireEquitySecuritiesFvNi_d22f6b42-a2c8-4bba-af9e-f86e53124457_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_PaymentsToAcquireEquitySecuritiesFvNi" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Payments to Acquire Equity Securities, FV-NI</link:label>
    <link:label id="lab_us-gaap_PaymentsToAcquireEquitySecuritiesFvNi_label_en-US" xlink:label="lab_us-gaap_PaymentsToAcquireEquitySecuritiesFvNi" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Payments to Acquire Equity Securities, FV-NI</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsToAcquireEquitySecuritiesFvNi" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PaymentsToAcquireEquitySecuritiesFvNi"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PaymentsToAcquireEquitySecuritiesFvNi" xlink:to="lab_us-gaap_PaymentsToAcquireEquitySecuritiesFvNi" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_DeferredTaxLiabilityMember_17887fad-9308-4e76-b04d-21dd2c7f8b64_terseLabel_en-US" xlink:label="lab_sigi_DeferredTaxLiabilityMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Deferred tax liability</link:label>
    <link:label id="lab_sigi_DeferredTaxLiabilityMember_label_en-US" xlink:label="lab_sigi_DeferredTaxLiabilityMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Deferred tax liability [Member]</link:label>
    <link:label id="lab_sigi_DeferredTaxLiabilityMember_documentation_en-US" xlink:label="lab_sigi_DeferredTaxLiabilityMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Deferred tax liability line item on the balance sheet</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_DeferredTaxLiabilityMember" xlink:href="sigi-20211231.xsd#sigi_DeferredTaxLiabilityMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_DeferredTaxLiabilityMember" xlink:to="lab_sigi_DeferredTaxLiabilityMember" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_DebtToCapitalizationRatio_783e60cd-e973-4da3-8031-c2a50d3080e2_terseLabel_en-US" xlink:label="lab_sigi_DebtToCapitalizationRatio" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Debt-to-capitalization ratio, actual</link:label>
    <link:label id="lab_sigi_DebtToCapitalizationRatio_label_en-US" xlink:label="lab_sigi_DebtToCapitalizationRatio" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Debt To Capitalization Ratio</link:label>
    <link:label id="lab_sigi_DebtToCapitalizationRatio_documentation_en-US" xlink:label="lab_sigi_DebtToCapitalizationRatio" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">This element represents the debt-to-capitalization ratio which is calculated by taking the entity's debt and dividing by the sum of the entity's debt and stockholders' equity as of the balance sheet date.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_DebtToCapitalizationRatio" xlink:href="sigi-20211231.xsd#sigi_DebtToCapitalizationRatio"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_DebtToCapitalizationRatio" xlink:to="lab_sigi_DebtToCapitalizationRatio" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_AxisReinsuranceCompanyMember_950ba011-a46d-4b39-872e-7b35c4d504c4_terseLabel_en-US" xlink:label="lab_sigi_AxisReinsuranceCompanyMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">AXIS Reinsurance Company [Member]</link:label>
    <link:label id="lab_sigi_AxisReinsuranceCompanyMember_label_en-US" xlink:label="lab_sigi_AxisReinsuranceCompanyMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Axis Reinsurance Company [Member]</link:label>
    <link:label id="lab_sigi_AxisReinsuranceCompanyMember_documentation_en-US" xlink:label="lab_sigi_AxisReinsuranceCompanyMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Represents AXIS Reinsurance Company.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_AxisReinsuranceCompanyMember" xlink:href="sigi-20211231.xsd#sigi_AxisReinsuranceCompanyMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_AxisReinsuranceCompanyMember" xlink:to="lab_sigi_AxisReinsuranceCompanyMember" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_LeaseExpenseTable_b2518ea3-54c7-415b-88fd-424e41331090_terseLabel_en-US" xlink:label="lab_sigi_LeaseExpenseTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Lease Expense [Table]</link:label>
    <link:label id="lab_sigi_LeaseExpenseTable_label_en-US" xlink:label="lab_sigi_LeaseExpenseTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Lease Expense [Table]</link:label>
    <link:label id="lab_sigi_LeaseExpenseTable_documentation_en-US" xlink:label="lab_sigi_LeaseExpenseTable" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Line Items for Components of lease expense, including operating leaess, finance leases, variable costs, and short term leases.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_LeaseExpenseTable" xlink:href="sigi-20211231.xsd#sigi_LeaseExpenseTable"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_LeaseExpenseTable" xlink:to="lab_sigi_LeaseExpenseTable" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_ConsolidatedNetWorthActual_ea5a2d5f-5c1b-4f22-a1ab-b6ca0744269b_terseLabel_en-US" xlink:label="lab_sigi_ConsolidatedNetWorthActual" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Consolidated Net Worth, Actual</link:label>
    <link:label id="lab_sigi_ConsolidatedNetWorthActual_label_en-US" xlink:label="lab_sigi_ConsolidatedNetWorthActual" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Consolidated Net Worth, Actual</link:label>
    <link:label id="lab_sigi_ConsolidatedNetWorthActual_documentation_en-US" xlink:label="lab_sigi_ConsolidatedNetWorthActual" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">This element represents the consolidated net worth of the entity that is calculated based on the line of credit requirements.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_ConsolidatedNetWorthActual" xlink:href="sigi-20211231.xsd#sigi_ConsolidatedNetWorthActual"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_ConsolidatedNetWorthActual" xlink:to="lab_sigi_ConsolidatedNetWorthActual" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_LineOfBusinessBySegmentAxis_198bb264-00b5-4b35-8d6f-12391c7d45d2_terseLabel_en-US" xlink:label="lab_sigi_LineOfBusinessBySegmentAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Line Of Business By Segment [Axis]</link:label>
    <link:label id="lab_sigi_LineOfBusinessBySegmentAxis_label_en-US" xlink:label="lab_sigi_LineOfBusinessBySegmentAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Line Of Business By Segment [Axis]</link:label>
    <link:label id="lab_sigi_LineOfBusinessBySegmentAxis_documentation_en-US" xlink:label="lab_sigi_LineOfBusinessBySegmentAxis" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Information by line of business segments.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_LineOfBusinessBySegmentAxis" xlink:href="sigi-20211231.xsd#sigi_LineOfBusinessBySegmentAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_LineOfBusinessBySegmentAxis" xlink:to="lab_sigi_LineOfBusinessBySegmentAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation_d00ab430-d3a3-43aa-aa04-0d4e86c08fb0_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Share-based Payment Arrangement, Decrease for Tax Withholding Obligation</link:label>
    <link:label id="lab_us-gaap_AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation_label_en-US" xlink:label="lab_us-gaap_AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Share-based Payment Arrangement, Decrease for Tax Withholding Obligation</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation" xlink:to="lab_us-gaap_AdjustmentsRelatedToTaxWithholdingForShareBasedCompensation" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized_a6580a28-8a63-4618-bec0-a2b3799dd6ef_terseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized" xlink:to="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardNumberOfSharesAuthorized" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_OperatingLeasePayments_29ebb737-55b6-4e38-b0b7-d2cd98fb75a2_terseLabel_en-US" xlink:label="lab_us-gaap_OperatingLeasePayments" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Operating cash flows from operating leases</link:label>
    <link:label id="lab_us-gaap_OperatingLeasePayments_label_en-US" xlink:label="lab_us-gaap_OperatingLeasePayments" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Operating Lease, Payments</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OperatingLeasePayments" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OperatingLeasePayments"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OperatingLeasePayments" xlink:to="lab_us-gaap_OperatingLeasePayments" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_NonCreditPortionofOtherThanTemporaryImpairmentsRecognizedinOtherComprehensiveIncome_e5d2bf3e-98c5-44c9-a1eb-df617138d738_terseLabel_en-US" xlink:label="lab_sigi_NonCreditPortionofOtherThanTemporaryImpairmentsRecognizedinOtherComprehensiveIncome" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Unrealized losses on securities with credit loss recognized in earnings</link:label>
    <link:label id="lab_sigi_NonCreditPortionofOtherThanTemporaryImpairmentsRecognizedinOtherComprehensiveIncome_label_en-US" xlink:label="lab_sigi_NonCreditPortionofOtherThanTemporaryImpairmentsRecognizedinOtherComprehensiveIncome" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Non-Credit Portion of Other-Than-Temporary Impairments Recognized in Other Comprehensive Income</link:label>
    <link:label id="lab_sigi_NonCreditPortionofOtherThanTemporaryImpairmentsRecognizedinOtherComprehensiveIncome_documentation_en-US" xlink:label="lab_sigi_NonCreditPortionofOtherThanTemporaryImpairmentsRecognizedinOtherComprehensiveIncome" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Non-credit portion of current other-than-temporary impairment losses on fixed maturity securities recognized in other comprehensive income net of tax. This item does not include changes in appreciation or loss in value.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_NonCreditPortionofOtherThanTemporaryImpairmentsRecognizedinOtherComprehensiveIncome" xlink:href="sigi-20211231.xsd#sigi_NonCreditPortionofOtherThanTemporaryImpairmentsRecognizedinOtherComprehensiveIncome"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_NonCreditPortionofOtherThanTemporaryImpairmentsRecognizedinOtherComprehensiveIncome" xlink:to="lab_sigi_NonCreditPortionofOtherThanTemporaryImpairmentsRecognizedinOtherComprehensiveIncome" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_PreferredStockDividendRatePercentage_8ce8e01e-53b0-4c1c-bc71-0b86b57a2dbf_terseLabel_en-US" xlink:label="lab_us-gaap_PreferredStockDividendRatePercentage" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Preferred Stock, Dividend Rate, Percentage</link:label>
    <link:label id="lab_us-gaap_PreferredStockDividendRatePercentage_label_en-US" xlink:label="lab_us-gaap_PreferredStockDividendRatePercentage" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Preferred Stock, Dividend Rate, Percentage</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockDividendRatePercentage" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PreferredStockDividendRatePercentage"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PreferredStockDividendRatePercentage" xlink:to="lab_us-gaap_PreferredStockDividendRatePercentage" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_PaymentsForCommissions_1c3fadcd-b596-428d-b55e-19c802a67a44_terseLabel_en-US" xlink:label="lab_us-gaap_PaymentsForCommissions" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Commissions paid to Rue Insurance</link:label>
    <link:label id="lab_us-gaap_PaymentsForCommissions_label_en-US" xlink:label="lab_us-gaap_PaymentsForCommissions" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Payments for Commissions</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PaymentsForCommissions" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PaymentsForCommissions"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PaymentsForCommissions" xlink:to="lab_us-gaap_PaymentsForCommissions" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ScheduleOfHeldToMaturitySecuritiesTable_17c8728b-ecbb-48a2-a264-e59f3fc0efbf_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfHeldToMaturitySecuritiesTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Debt Securities, Held-to-maturity [Table]</link:label>
    <link:label id="lab_us-gaap_ScheduleOfHeldToMaturitySecuritiesTable_label_en-US" xlink:label="lab_us-gaap_ScheduleOfHeldToMaturitySecuritiesTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Debt Securities, Held-to-maturity [Table]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfHeldToMaturitySecuritiesTable" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfHeldToMaturitySecuritiesTable"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfHeldToMaturitySecuritiesTable" xlink:to="lab_us-gaap_ScheduleOfHeldToMaturitySecuritiesTable" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_BusinessOwnersPoliciesMember_8733c1cf-cc47-40c4-9b12-18bec8396c41_terseLabel_en-US" xlink:label="lab_sigi_BusinessOwnersPoliciesMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Business Owners' Policies [Member]</link:label>
    <link:label id="lab_sigi_BusinessOwnersPoliciesMember_label_en-US" xlink:label="lab_sigi_BusinessOwnersPoliciesMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Business Owners Policies [Member]</link:label>
    <link:label id="lab_sigi_BusinessOwnersPoliciesMember_documentation_en-US" xlink:label="lab_sigi_BusinessOwnersPoliciesMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Represents insurance coverage provided for business owners' policies</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_BusinessOwnersPoliciesMember" xlink:href="sigi-20211231.xsd#sigi_BusinessOwnersPoliciesMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_BusinessOwnersPoliciesMember" xlink:to="lab_sigi_BusinessOwnersPoliciesMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ReinsuranceRecoverableForUnpaidClaimsAndClaimsAdjustments_8d5d2754-72ae-4ea8-a0b4-c8feba27ed6e_periodStartLabel_en-US" xlink:label="lab_us-gaap_ReinsuranceRecoverableForUnpaidClaimsAndClaimsAdjustments" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Less: reinsurance recoverable on unpaid loss and loss expense, at beginning of year</link:label>
    <link:label id="lab_us-gaap_ReinsuranceRecoverableForUnpaidClaimsAndClaimsAdjustments_bb446ff4-d651-42ed-bc48-08cfe4b2b02d_periodEndLabel_en-US" xlink:label="lab_us-gaap_ReinsuranceRecoverableForUnpaidClaimsAndClaimsAdjustments" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Add: reinsurance recoverable on unpaid loss and loss expense, at end of year</link:label>
    <link:label id="lab_us-gaap_ReinsuranceRecoverableForUnpaidClaimsAndClaimsAdjustments_aa9821d4-be67-4f16-b868-ebabaaf95694_terseLabel_en-US" xlink:label="lab_us-gaap_ReinsuranceRecoverableForUnpaidClaimsAndClaimsAdjustments" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Reinsurance Recoverable for Unpaid Claims and Claims Adjustments</link:label>
    <link:label id="lab_us-gaap_ReinsuranceRecoverableForUnpaidClaimsAndClaimsAdjustments_label_en-US" xlink:label="lab_us-gaap_ReinsuranceRecoverableForUnpaidClaimsAndClaimsAdjustments" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Reinsurance Recoverable for Unpaid Claims and Claims Adjustments</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReinsuranceRecoverableForUnpaidClaimsAndClaimsAdjustments" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ReinsuranceRecoverableForUnpaidClaimsAndClaimsAdjustments"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ReinsuranceRecoverableForUnpaidClaimsAndClaimsAdjustments" xlink:to="lab_us-gaap_ReinsuranceRecoverableForUnpaidClaimsAndClaimsAdjustments" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_ShareBasedCompensationLiabilityAwardsAmountOfLiability_203a88d2-affb-42e4-9ea8-cd3fa9808ae3_terseLabel_en-US" xlink:label="lab_sigi_ShareBasedCompensationLiabilityAwardsAmountOfLiability" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Share Based Compensation Liability Awards Amount Of Liability</link:label>
    <link:label id="lab_sigi_ShareBasedCompensationLiabilityAwardsAmountOfLiability_label_en-US" xlink:label="lab_sigi_ShareBasedCompensationLiabilityAwardsAmountOfLiability" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Share Based Compensation Liability Awards Amount Of Liability</link:label>
    <link:label id="lab_sigi_ShareBasedCompensationLiabilityAwardsAmountOfLiability_documentation_en-US" xlink:label="lab_sigi_ShareBasedCompensationLiabilityAwardsAmountOfLiability" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">The liability recorded in connection with our Cash Incentive Plan.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_ShareBasedCompensationLiabilityAwardsAmountOfLiability" xlink:href="sigi-20211231.xsd#sigi_ShareBasedCompensationLiabilityAwardsAmountOfLiability"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_ShareBasedCompensationLiabilityAwardsAmountOfLiability" xlink:to="lab_sigi_ShareBasedCompensationLiabilityAwardsAmountOfLiability" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DebtInstrumentCarryingAmount_4c161dd0-720e-4bdf-9d44-24eea736239a_terseLabel_en-US" xlink:label="lab_us-gaap_DebtInstrumentCarryingAmount" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Long-term Debt, Gross</link:label>
    <link:label id="lab_us-gaap_DebtInstrumentCarryingAmount_label_en-US" xlink:label="lab_us-gaap_DebtInstrumentCarryingAmount" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Long-term Debt, Gross</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtInstrumentCarryingAmount" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtInstrumentCarryingAmount"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DebtInstrumentCarryingAmount" xlink:to="lab_us-gaap_DebtInstrumentCarryingAmount" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_RealAssetsEquityMemberMember_868a0561-539b-4b91-85c0-8e1ab1d72281_terseLabel_en-US" xlink:label="lab_sigi_RealAssetsEquityMemberMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Real Assets Equity [Member]</link:label>
    <link:label id="lab_sigi_RealAssetsEquityMemberMember_label_en-US" xlink:label="lab_sigi_RealAssetsEquityMemberMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Real Assets Equity [Member] [Member]</link:label>
    <link:label id="lab_sigi_RealAssetsEquityMemberMember_documentation_en-US" xlink:label="lab_sigi_RealAssetsEquityMemberMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">An investment fund that is indirectly invested in public and private debt and equity investments in a range of real estate strategies, including but not limited to real estate, infrastructure, timberland and agriculture/farmland.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_RealAssetsEquityMemberMember" xlink:href="sigi-20211231.xsd#sigi_RealAssetsEquityMemberMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_RealAssetsEquityMemberMember" xlink:to="lab_sigi_RealAssetsEquityMemberMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ClaimsDevelopmentLineItems_bc1b0a16-9d2b-454b-b35c-7b2775a21939_terseLabel_en-US" xlink:label="lab_us-gaap_ClaimsDevelopmentLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Claims Development [Line Items]</link:label>
    <link:label id="lab_us-gaap_ClaimsDevelopmentLineItems_label_en-US" xlink:label="lab_us-gaap_ClaimsDevelopmentLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Claims Development [Line Items]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ClaimsDevelopmentLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ClaimsDevelopmentLineItems"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ClaimsDevelopmentLineItems" xlink:to="lab_us-gaap_ClaimsDevelopmentLineItems" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_SupplementaryInsuranceInformationLiabilityForFuturePolicyBenefitsLossesClaimsAndLossExpenseReserves_b8c72352-8151-4c01-9e87-a350463bcd58_terseLabel_en-US" xlink:label="lab_us-gaap_SupplementaryInsuranceInformationLiabilityForFuturePolicyBenefitsLossesClaimsAndLossExpenseReserves" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Reserve for loss and loss expenses</link:label>
    <link:label id="lab_us-gaap_SupplementaryInsuranceInformationLiabilityForFuturePolicyBenefitsLossesClaimsAndLossExpenseReserves_label_en-US" xlink:label="lab_us-gaap_SupplementaryInsuranceInformationLiabilityForFuturePolicyBenefitsLossesClaimsAndLossExpenseReserves" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">SEC Schedule, 12-16, Insurance Companies, Supplementary Insurance Information, Liability for Future Policy Benefit, Loss, Claim and Loss Expense</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SupplementaryInsuranceInformationLiabilityForFuturePolicyBenefitsLossesClaimsAndLossExpenseReserves" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SupplementaryInsuranceInformationLiabilityForFuturePolicyBenefitsLossesClaimsAndLossExpenseReserves"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SupplementaryInsuranceInformationLiabilityForFuturePolicyBenefitsLossesClaimsAndLossExpenseReserves" xlink:to="lab_us-gaap_SupplementaryInsuranceInformationLiabilityForFuturePolicyBenefitsLossesClaimsAndLossExpenseReserves" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FinanceLeaseRightOfUseAsset_f0852544-34e5-4ac6-a0b8-b83db39bcab6_verboseLabel_en-US" xlink:label="lab_us-gaap_FinanceLeaseRightOfUseAsset" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Finance leases, Property and equipment - at cost, net of accumulated depreciation and amortization</link:label>
    <link:label id="lab_us-gaap_FinanceLeaseRightOfUseAsset_label_en-US" xlink:label="lab_us-gaap_FinanceLeaseRightOfUseAsset" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Finance Lease, Right-of-Use Asset, after Accumulated Amortization</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseRightOfUseAsset" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinanceLeaseRightOfUseAsset"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FinanceLeaseRightOfUseAsset" xlink:to="lab_us-gaap_FinanceLeaseRightOfUseAsset" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AssetsFairValueDisclosure_16ff10e1-256a-4408-8e6a-2c7d0efc5c7a_totalLabel_en-US" xlink:label="lab_us-gaap_AssetsFairValueDisclosure" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Total Assets</link:label>
    <link:label id="lab_us-gaap_AssetsFairValueDisclosure_76ed35d3-0338-46cd-bf8a-bd627587bee4_terseLabel_en-US" xlink:label="lab_us-gaap_AssetsFairValueDisclosure" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Assets, Fair Value Disclosure</link:label>
    <link:label id="lab_us-gaap_AssetsFairValueDisclosure_label_en-US" xlink:label="lab_us-gaap_AssetsFairValueDisclosure" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Assets, Fair Value Disclosure</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AssetsFairValueDisclosure" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AssetsFairValueDisclosure"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AssetsFairValueDisclosure" xlink:to="lab_us-gaap_AssetsFairValueDisclosure" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_DebtSecuritiesAvailableForSaleCreditLossExpense_3667950d-8021-454f-a81b-dbc7c2b406b7_negatedTerseLabel_en-US" xlink:label="lab_sigi_DebtSecuritiesAvailableForSaleCreditLossExpense" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Amounts reclassified into net income: Credit loss expense</link:label>
    <link:label id="lab_sigi_DebtSecuritiesAvailableForSaleCreditLossExpense_label_en-US" xlink:label="lab_sigi_DebtSecuritiesAvailableForSaleCreditLossExpense" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Debt Securities, Available-for-sale, Credit loss expense</link:label>
    <link:label id="lab_sigi_DebtSecuritiesAvailableForSaleCreditLossExpense_documentation_en-US" xlink:label="lab_sigi_DebtSecuritiesAvailableForSaleCreditLossExpense" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Amount after tax of reclassification adjustment from accumulated other comprehensive income for unrealized amounts realized upon a credit-related impairment loss.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_DebtSecuritiesAvailableForSaleCreditLossExpense" xlink:href="sigi-20211231.xsd#sigi_DebtSecuritiesAvailableForSaleCreditLossExpense"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_DebtSecuritiesAvailableForSaleCreditLossExpense" xlink:to="lab_sigi_DebtSecuritiesAvailableForSaleCreditLossExpense" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_DepositAdministrationContractsMember_0fa3eacc-b143-46cd-915e-d8ee8293c651_terseLabel_en-US" xlink:label="lab_sigi_DepositAdministrationContractsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Deposit Administration Contracts [Member]</link:label>
    <link:label id="lab_sigi_DepositAdministrationContractsMember_label_en-US" xlink:label="lab_sigi_DepositAdministrationContractsMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Deposit Administration Contracts [Member]</link:label>
    <link:label id="lab_sigi_DepositAdministrationContractsMember_documentation_en-US" xlink:label="lab_sigi_DepositAdministrationContractsMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Represents cash deposited with an insurer and placed in the insurer's general investment account typically highlighting short-term products. At a plan participant's retirement, the insurer withdraws the funds from the general account to pay the retiree.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_DepositAdministrationContractsMember" xlink:href="sigi-20211231.xsd#sigi_DepositAdministrationContractsMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_DepositAdministrationContractsMember" xlink:to="lab_sigi_DepositAdministrationContractsMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_SoftwareDevelopmentMember_80bcdbb9-6609-476a-a1cb-61aed81b51d1_terseLabel_en-US" xlink:label="lab_us-gaap_SoftwareDevelopmentMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Internally developed software [Member]</link:label>
    <link:label id="lab_us-gaap_SoftwareDevelopmentMember_label_en-US" xlink:label="lab_us-gaap_SoftwareDevelopmentMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Software Development [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SoftwareDevelopmentMember" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SoftwareDevelopmentMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SoftwareDevelopmentMember" xlink:to="lab_us-gaap_SoftwareDevelopmentMember" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_OCIReclassificationAdjustmentFromAOCIForWriteDownOfSecuritiesNetOfTax_1c8059e3-4df9-4b93-8ecd-6dabaa41119e_negatedTerseLabel_en-US" xlink:label="lab_sigi_OCIReclassificationAdjustmentFromAOCIForWriteDownOfSecuritiesNetOfTax" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Amounts reclassified into net income: Net realized losses on disposals and losses on intent-to-sell available-for-sale securities</link:label>
    <link:label id="lab_sigi_OCIReclassificationAdjustmentFromAOCIForWriteDownOfSecuritiesNetOfTax_label_en-US" xlink:label="lab_sigi_OCIReclassificationAdjustmentFromAOCIForWriteDownOfSecuritiesNetOfTax" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">OCI, Reclassification Adjustment from AOCI for Write-down of Securities, Net of Tax</link:label>
    <link:label id="lab_sigi_OCIReclassificationAdjustmentFromAOCIForWriteDownOfSecuritiesNetOfTax_documentation_en-US" xlink:label="lab_sigi_OCIReclassificationAdjustmentFromAOCIForWriteDownOfSecuritiesNetOfTax" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Amount after tax of reclassification adjustment from accumulated other comprehensive income for unrealized amounts realized upon: (i) the disposal of; or (ii) the intent-to-sell write-down, of available-for-sale securities.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_OCIReclassificationAdjustmentFromAOCIForWriteDownOfSecuritiesNetOfTax" xlink:href="sigi-20211231.xsd#sigi_OCIReclassificationAdjustmentFromAOCIForWriteDownOfSecuritiesNetOfTax"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_OCIReclassificationAdjustmentFromAOCIForWriteDownOfSecuritiesNetOfTax" xlink:to="lab_sigi_OCIReclassificationAdjustmentFromAOCIForWriteDownOfSecuritiesNetOfTax" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_IncomeTaxExpenseBenefitContinuingOperationsAbstract_935765c9-dfd1-4902-b065-65268e0175d2_terseLabel_en-US" xlink:label="lab_us-gaap_IncomeTaxExpenseBenefitContinuingOperationsAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Federal income tax expense:</link:label>
    <link:label id="lab_us-gaap_IncomeTaxExpenseBenefitContinuingOperationsAbstract_label_en-US" xlink:label="lab_us-gaap_IncomeTaxExpenseBenefitContinuingOperationsAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Income Tax Expense (Benefit), Continuing Operations [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefitContinuingOperationsAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeTaxExpenseBenefitContinuingOperationsAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncomeTaxExpenseBenefitContinuingOperationsAbstract" xlink:to="lab_us-gaap_IncomeTaxExpenseBenefitContinuingOperationsAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LiabilitiesAndStockholdersEquity_219e77d8-afe3-439a-a372-276a66498150_totalLabel_en-US" xlink:label="lab_us-gaap_LiabilitiesAndStockholdersEquity" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Total liabilities and stockholders&#8217; equity</link:label>
    <link:label id="lab_us-gaap_LiabilitiesAndStockholdersEquity_1f8a0a71-00d1-46af-9bed-529bb37f6d3d_terseLabel_en-US" xlink:label="lab_us-gaap_LiabilitiesAndStockholdersEquity" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Total liabilities and stockholders&#8217; equity</link:label>
    <link:label id="lab_us-gaap_LiabilitiesAndStockholdersEquity_label_en-US" xlink:label="lab_us-gaap_LiabilitiesAndStockholdersEquity" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Liabilities and Equity</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquity" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquity"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LiabilitiesAndStockholdersEquity" xlink:to="lab_us-gaap_LiabilitiesAndStockholdersEquity" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_AgentStockPurchasePlanMember_c6839910-e7fd-4238-96f6-4118822853c6_terseLabel_en-US" xlink:label="lab_sigi_AgentStockPurchasePlanMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Agent Stock Purchase Plan [Member]</link:label>
    <link:label id="lab_sigi_AgentStockPurchasePlanMember_label_en-US" xlink:label="lab_sigi_AgentStockPurchasePlanMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Agent Stock Purchase Plan [Member]</link:label>
    <link:label id="lab_sigi_AgentStockPurchasePlanMember_documentation_en-US" xlink:label="lab_sigi_AgentStockPurchasePlanMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">The company's agent stock purchase plan which provides for quarterly offerings in which independent insurance agencies, and certain eligible persons associated with the agencies can purchase the Parent's common stock.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_AgentStockPurchasePlanMember" xlink:href="sigi-20211231.xsd#sigi_AgentStockPurchasePlanMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_AgentStockPurchasePlanMember" xlink:to="lab_sigi_AgentStockPurchasePlanMember" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_OperatingSegmentsSIGIMember_0f840d79-24d7-4201-ab7e-bfcaffc4610c_terseLabel_en-US" xlink:label="lab_sigi_OperatingSegmentsSIGIMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Operating Segments [Member]</link:label>
    <link:label id="lab_sigi_OperatingSegmentsSIGIMember_label_en-US" xlink:label="lab_sigi_OperatingSegmentsSIGIMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Operating Segments SIGI [Member]</link:label>
    <link:label id="lab_sigi_OperatingSegmentsSIGIMember_documentation_en-US" xlink:label="lab_sigi_OperatingSegmentsSIGIMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Identifies components of an entity that engage in business activities from which they may earn revenue and incur expenses, including transactions with other components of the same entity.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_OperatingSegmentsSIGIMember" xlink:href="sigi-20211231.xsd#sigi_OperatingSegmentsSIGIMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_OperatingSegmentsSIGIMember" xlink:to="lab_sigi_OperatingSegmentsSIGIMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFive_346f1949-8a21-450c-a289-028346d4fd04_terseLabel_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFive" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Operating Lease Liability, Due Year Five</link:label>
    <link:label id="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFive_label_en-US" xlink:label="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFive" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Lessee, Operating Lease, Liability, to be Paid, Year Five</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFive" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFive"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFive" xlink:to="lab_us-gaap_LesseeOperatingLeaseLiabilityPaymentsDueYearFive" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_DisclosureofESPPandASPPShareIssuanceAbstract_4362a587-c5b1-4243-99c1-530770b57724_terseLabel_en-US" xlink:label="lab_sigi_DisclosureofESPPandASPPShareIssuanceAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Disclosure of ESPP and ASPP Share Issuance [Abstract]</link:label>
    <link:label id="lab_sigi_DisclosureofESPPandASPPShareIssuanceAbstract_label_en-US" xlink:label="lab_sigi_DisclosureofESPPandASPPShareIssuanceAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Disclosure of ESPP and ASPP Share Issuance [Abstract]</link:label>
    <link:label id="lab_sigi_DisclosureofESPPandASPPShareIssuanceAbstract_documentation_en-US" xlink:label="lab_sigi_DisclosureofESPPandASPPShareIssuanceAbstract" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Disclosure of ESPP and ASPP Share Issuance [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_DisclosureofESPPandASPPShareIssuanceAbstract" xlink:href="sigi-20211231.xsd#sigi_DisclosureofESPPandASPPShareIssuanceAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_DisclosureofESPPandASPPShareIssuanceAbstract" xlink:to="lab_sigi_DisclosureofESPPandASPPShareIssuanceAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice_a3c217e2-246e-4e0c-9548-486f7c59f599_terseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Exercised in 2021, weighted average exercise price</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Share-based Compensation Arrangements by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice" xlink:to="lab_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardOptionsExercisesInPeriodWeightedAverageExercisePrice" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RestrictedCash_48ba476a-e5b0-4fc8-91ce-2b04d2330d54_terseLabel_en-US" xlink:label="lab_us-gaap_RestrictedCash" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Restricted cash</link:label>
    <link:label id="lab_us-gaap_RestrictedCash_label_en-US" xlink:label="lab_us-gaap_RestrictedCash" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Restricted Cash</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RestrictedCash" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RestrictedCash"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RestrictedCash" xlink:to="lab_us-gaap_RestrictedCash" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesWithinOneYearNetCarryingAmount_2fc73170-9aa5-4447-8606-2efe8b44212f_terseLabel_en-US" xlink:label="lab_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesWithinOneYearNetCarryingAmount" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">HTM due in one year or less carrying value</link:label>
    <link:label id="lab_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesWithinOneYearNetCarryingAmount_label_en-US" xlink:label="lab_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesWithinOneYearNetCarryingAmount" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Debt Securities, Held-to-Maturity, Amortized Cost, after Allowance for Credit Loss, Maturity, Allocated and Single Maturity Date, Year One</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesWithinOneYearNetCarryingAmount" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_HeldToMaturitySecuritiesDebtMaturitiesWithinOneYearNetCarryingAmount"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesWithinOneYearNetCarryingAmount" xlink:to="lab_us-gaap_HeldToMaturitySecuritiesDebtMaturitiesWithinOneYearNetCarryingAmount" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_USGovernmentAgenciesDebtSecuritiesMember_f2dead66-6fe3-493c-a1e2-2350536cb479_terseLabel_en-US" xlink:label="lab_us-gaap_USGovernmentAgenciesDebtSecuritiesMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">US Government Agencies Debt Securities [Member]</link:label>
    <link:label id="lab_us-gaap_USGovernmentAgenciesDebtSecuritiesMember_label_en-US" xlink:label="lab_us-gaap_USGovernmentAgenciesDebtSecuritiesMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">US Government Agencies Debt Securities [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_USGovernmentAgenciesDebtSecuritiesMember" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_USGovernmentAgenciesDebtSecuritiesMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_USGovernmentAgenciesDebtSecuritiesMember" xlink:to="lab_us-gaap_USGovernmentAgenciesDebtSecuritiesMember" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_MaximumexposuretocreditconcentrationriskoftheCompanysstockholdersequityotherthancertainU.S.governmentagencies_ca9f7d31-253b-405d-aafa-8f9ac1fa162c_terseLabel_en-US" xlink:label="lab_sigi_MaximumexposuretocreditconcentrationriskoftheCompanysstockholdersequityotherthancertainU.S.governmentagencies" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Maximum exposure to credit concentration risk of the Company's stockholder's equity other than certain U.S. government agencies</link:label>
    <link:label id="lab_sigi_MaximumexposuretocreditconcentrationriskoftheCompanysstockholdersequityotherthancertainU.S.governmentagencies_label_en-US" xlink:label="lab_sigi_MaximumexposuretocreditconcentrationriskoftheCompanysstockholdersequityotherthancertainU.S.governmentagencies" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Maximum exposure to credit concentration risk of the Company's stockholder's equity other than certain U.S. government agencies</link:label>
    <link:label id="lab_sigi_MaximumexposuretocreditconcentrationriskoftheCompanysstockholdersequityotherthancertainU.S.governmentagencies_documentation_en-US" xlink:label="lab_sigi_MaximumexposuretocreditconcentrationriskoftheCompanysstockholdersequityotherthancertainU.S.governmentagencies" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Maximum exposure to credit concentration risk of the Company's stockholder's equity other than certain U.S. government agencies</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_MaximumexposuretocreditconcentrationriskoftheCompanysstockholdersequityotherthancertainU.S.governmentagencies" xlink:href="sigi-20211231.xsd#sigi_MaximumexposuretocreditconcentrationriskoftheCompanysstockholdersequityotherthancertainU.S.governmentagencies"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_MaximumexposuretocreditconcentrationriskoftheCompanysstockholdersequityotherthancertainU.S.governmentagencies" xlink:to="lab_sigi_MaximumexposuretocreditconcentrationriskoftheCompanysstockholdersequityotherthancertainU.S.governmentagencies" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansTax_8a93f30a-f06a-40cd-b1b9-ff490c392e42_negatedTotalLabel_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansTax" xlink:role="http://www.xbrl.org/2009/role/negatedTotalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Defined pension and other post-retirement benefit plans, Tax</link:label>
    <link:label id="lab_us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansTax_label_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansTax" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, Tax</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansTax" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansTax"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansTax" xlink:to="lab_us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansTax" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_GlobalEquityMember_67c672d1-9df0-4a52-ae34-eee2f30cfa77_terseLabel_en-US" xlink:label="lab_sigi_GlobalEquityMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Global Equity [Member]</link:label>
    <link:label id="lab_sigi_GlobalEquityMember_label_en-US" xlink:label="lab_sigi_GlobalEquityMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Global Equity [Member]</link:label>
    <link:label id="lab_sigi_GlobalEquityMember_documentation_en-US" xlink:label="lab_sigi_GlobalEquityMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Represents investments in both US and non-US equity securities.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_GlobalEquityMember" xlink:href="sigi-20211231.xsd#sigi_GlobalEquityMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_GlobalEquityMember" xlink:to="lab_sigi_GlobalEquityMember" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_InvestmentYieldsAssumedInPremiumDeficiencyAssessment_cd9e49e2-92c6-4323-a053-9eed9e0e9cc3_verboseLabel_en-US" xlink:label="lab_sigi_InvestmentYieldsAssumedInPremiumDeficiencyAssessment" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Investment yields before tax assumed in premium deficiency assessment</link:label>
    <link:label id="lab_sigi_InvestmentYieldsAssumedInPremiumDeficiencyAssessment_label_en-US" xlink:label="lab_sigi_InvestmentYieldsAssumedInPremiumDeficiencyAssessment" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Investment Yields Assumed In Premium Deficiency Assessment</link:label>
    <link:label id="lab_sigi_InvestmentYieldsAssumedInPremiumDeficiencyAssessment_documentation_en-US" xlink:label="lab_sigi_InvestmentYieldsAssumedInPremiumDeficiencyAssessment" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">This element represents the investment yields assumed in the premium deficiency assessment, which are based on the entity's actual average investment yield before tax as of the calculation date.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_InvestmentYieldsAssumedInPremiumDeficiencyAssessment" xlink:href="sigi-20211231.xsd#sigi_InvestmentYieldsAssumedInPremiumDeficiencyAssessment"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_InvestmentYieldsAssumedInPremiumDeficiencyAssessment" xlink:to="lab_sigi_InvestmentYieldsAssumedInPremiumDeficiencyAssessment" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ShortTermDebtTypeDomain_07ee2110-581e-4d92-ab62-8ba84033c941_terseLabel_en-US" xlink:label="lab_us-gaap_ShortTermDebtTypeDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Short-term Debt, Type [Domain]</link:label>
    <link:label id="lab_us-gaap_ShortTermDebtTypeDomain_label_en-US" xlink:label="lab_us-gaap_ShortTermDebtTypeDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Short-term Debt, Type [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermDebtTypeDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShortTermDebtTypeDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShortTermDebtTypeDomain" xlink:to="lab_us-gaap_ShortTermDebtTypeDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_InvestmentCommitmentsTableTextBlock_1381024a-a2b3-4cb9-8f7a-e72b311bcd06_verboseLabel_en-US" xlink:label="lab_sigi_InvestmentCommitmentsTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Investments Classified by Contractual Maturity Date [Table Text Block]</link:label>
    <link:label id="lab_sigi_InvestmentCommitmentsTableTextBlock_label_en-US" xlink:label="lab_sigi_InvestmentCommitmentsTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Investment Commitments [Table Text Block]</link:label>
    <link:label id="lab_sigi_InvestmentCommitmentsTableTextBlock_documentation_en-US" xlink:label="lab_sigi_InvestmentCommitmentsTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Tabular disclosure of commitments that may require us to invest additional amounts into our investment portfolio.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_InvestmentCommitmentsTableTextBlock" xlink:href="sigi-20211231.xsd#sigi_InvestmentCommitmentsTableTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_InvestmentCommitmentsTableTextBlock" xlink:to="lab_sigi_InvestmentCommitmentsTableTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_EarningsPerShareTextBlock_bfef6c56-b5a2-415d-b8da-0facb665fb32_terseLabel_en-US" xlink:label="lab_us-gaap_EarningsPerShareTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Earnings Per Share</link:label>
    <link:label id="lab_us-gaap_EarningsPerShareTextBlock_label_en-US" xlink:label="lab_us-gaap_EarningsPerShareTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Earnings Per Share [Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_EarningsPerShareTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_EarningsPerShareTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EarningsPerShareTextBlock" xlink:to="lab_us-gaap_EarningsPerShareTextBlock" xlink:type="arc" order="1"/>
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    <link:label id="lab_us-gaap_RevenueRecognitionPolicyTextBlock_label_en-US" xlink:label="lab_us-gaap_RevenueRecognitionPolicyTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Revenue [Policy Text Block]</link:label>
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    <link:label id="lab_sigi_TotalfederalandstatepoolsMember_2cc1f57a-7492-49e3-a708-2e59233a7046_terseLabel_en-US" xlink:label="lab_sigi_TotalfederalandstatepoolsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Total federal and state pools [Member]</link:label>
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    <link:label id="lab_sigi_TotalfederalandstatepoolsMember_documentation_en-US" xlink:label="lab_sigi_TotalfederalandstatepoolsMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Total reinsurers included within the federal and state pools.</link:label>
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    <link:label id="lab_us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodTax_d0ed93cd-3890-493e-ac02-0315549e1f34_terseLabel_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodTax" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Net actuarial gain (loss), Tax</link:label>
    <link:label id="lab_us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodTax_label_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodTax" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss) Arising During Period, Tax</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodTax" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodTax"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodTax" xlink:to="lab_us-gaap_OtherComprehensiveIncomeDefinedBenefitPlansNetUnamortizedGainLossArisingDuringPeriodTax" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_RemainingReinsuranceAfterAllowanceForCreditLoss_00b2e8fc-607a-4430-a0f3-c1d5408d3d36_terseLabel_en-US" xlink:label="lab_sigi_RemainingReinsuranceAfterAllowanceForCreditLoss" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Remaining Reinsurance, after Allowance for Credit Loss</link:label>
    <link:label id="lab_sigi_RemainingReinsuranceAfterAllowanceForCreditLoss_label_en-US" xlink:label="lab_sigi_RemainingReinsuranceAfterAllowanceForCreditLoss" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Remaining Reinsurance, after Allowance for Credit Loss</link:label>
    <link:label id="lab_sigi_RemainingReinsuranceAfterAllowanceForCreditLoss_documentation_en-US" xlink:label="lab_sigi_RemainingReinsuranceAfterAllowanceForCreditLoss" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">This element represents the known and estimated amount of reinsurance recoverables and the unexpired portion of premiums ceded on policies in force, less all federal and state pools, as of the balance sheet date, net of allowance for Credit Loss</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_RemainingReinsuranceAfterAllowanceForCreditLoss" xlink:href="sigi-20211231.xsd#sigi_RemainingReinsuranceAfterAllowanceForCreditLoss"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_RemainingReinsuranceAfterAllowanceForCreditLoss" xlink:to="lab_sigi_RemainingReinsuranceAfterAllowanceForCreditLoss" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_NonRatedReinsurerDomain_e27b584b-c3df-4021-877c-a31c01af3773_terseLabel_en-US" xlink:label="lab_sigi_NonRatedReinsurerDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Non Rated Reinsurer [Domain]</link:label>
    <link:label id="lab_sigi_NonRatedReinsurerDomain_label_en-US" xlink:label="lab_sigi_NonRatedReinsurerDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Non Rated Reinsurer [Domain]</link:label>
    <link:label id="lab_sigi_NonRatedReinsurerDomain_documentation_en-US" xlink:label="lab_sigi_NonRatedReinsurerDomain" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Non Rated Reinsurer</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_NonRatedReinsurerDomain" xlink:href="sigi-20211231.xsd#sigi_NonRatedReinsurerDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_NonRatedReinsurerDomain" xlink:to="lab_sigi_NonRatedReinsurerDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_TotalLeasesDueThereafter_f339299a-c624-4d6a-9be2-1d8445b5f511_terseLabel_en-US" xlink:label="lab_sigi_TotalLeasesDueThereafter" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Total Lease Due Thereafter</link:label>
    <link:label id="lab_sigi_TotalLeasesDueThereafter_label_en-US" xlink:label="lab_sigi_TotalLeasesDueThereafter" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Total Leases Due Thereafter</link:label>
    <link:label id="lab_sigi_TotalLeasesDueThereafter_documentation_en-US" xlink:label="lab_sigi_TotalLeasesDueThereafter" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Amount of lessee's undiscounted obligation for lease payments for finance and operating leases, due after the fifth fiscal year following the latest fiscal year for all leases.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_TotalLeasesDueThereafter" xlink:href="sigi-20211231.xsd#sigi_TotalLeasesDueThereafter"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_TotalLeasesDueThereafter" xlink:to="lab_sigi_TotalLeasesDueThereafter" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_Cash_1252fdc8-9295-4132-bd76-dc609aa9a542_terseLabel_en-US" xlink:label="lab_us-gaap_Cash" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Cash</link:label>
    <link:label id="lab_us-gaap_Cash_f4ab59cb-8291-4832-acab-1fface269e84_periodStartLabel_en-US" xlink:label="lab_us-gaap_Cash" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Cash, beginning of year</link:label>
    <link:label id="lab_us-gaap_Cash_31ec982e-9f1d-4835-9d42-1298601716a1_periodEndLabel_en-US" xlink:label="lab_us-gaap_Cash" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Cash, end of year</link:label>
    <link:label id="lab_us-gaap_Cash_label_en-US" xlink:label="lab_us-gaap_Cash" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Cash</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Cash" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_Cash"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_Cash" xlink:to="lab_us-gaap_Cash" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ReinsuranceRecoverablesOnPaidAndUnpaidLosses_fe2bd2a4-0a0d-4213-a076-d432d70e8d7b_terseLabel_en-US" xlink:label="lab_us-gaap_ReinsuranceRecoverablesOnPaidAndUnpaidLosses" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Reinsurance Recoverable for Paid and Unpaid Claims and Claims Adjustments</link:label>
    <link:label id="lab_us-gaap_ReinsuranceRecoverablesOnPaidAndUnpaidLosses_label_en-US" xlink:label="lab_us-gaap_ReinsuranceRecoverablesOnPaidAndUnpaidLosses" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Reinsurance Recoverable for Paid and Unpaid Claims and Claims Adjustments</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReinsuranceRecoverablesOnPaidAndUnpaidLosses" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ReinsuranceRecoverablesOnPaidAndUnpaidLosses"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ReinsuranceRecoverablesOnPaidAndUnpaidLosses" xlink:to="lab_us-gaap_ReinsuranceRecoverablesOnPaidAndUnpaidLosses" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ScheduleOfNetPeriodicBenefitCostNotYetRecognizedTableTextBlock_6bc4df09-1d3e-4c73-bedb-7fd5c063bef0_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfNetPeriodicBenefitCostNotYetRecognizedTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule of Amounts recognized in Accumulated Other than Comprehensive Income</link:label>
    <link:label id="lab_us-gaap_ScheduleOfNetPeriodicBenefitCostNotYetRecognizedTableTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfNetPeriodicBenefitCostNotYetRecognizedTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule of Net Periodic Benefit Cost Not yet Recognized [Table Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfNetPeriodicBenefitCostNotYetRecognizedTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfNetPeriodicBenefitCostNotYetRecognizedTableTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfNetPeriodicBenefitCostNotYetRecognizedTableTextBlock" xlink:to="lab_us-gaap_ScheduleOfNetPeriodicBenefitCostNotYetRecognizedTableTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_NetIncomeLossFromContinuingOperationsBeforeEquityInUndistributedIncomeOfSubsidiaries_d037eb75-f3e3-4869-892f-0abdbc7d4974_terseLabel_en-US" xlink:label="lab_sigi_NetIncomeLossFromContinuingOperationsBeforeEquityInUndistributedIncomeOfSubsidiaries" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Net income before equity in undistributed income of subsidiaries</link:label>
    <link:label id="lab_sigi_NetIncomeLossFromContinuingOperationsBeforeEquityInUndistributedIncomeOfSubsidiaries_label_en-US" xlink:label="lab_sigi_NetIncomeLossFromContinuingOperationsBeforeEquityInUndistributedIncomeOfSubsidiaries" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Net Income Loss From Continuing Operations Before Equity In Undistributed Income Of Subsidiaries</link:label>
    <link:label id="lab_sigi_NetIncomeLossFromContinuingOperationsBeforeEquityInUndistributedIncomeOfSubsidiaries_documentation_en-US" xlink:label="lab_sigi_NetIncomeLossFromContinuingOperationsBeforeEquityInUndistributedIncomeOfSubsidiaries" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">This element represents the income or loss from continuing operations attributable to the entity, after tax, which may also be defined as revenue less expenses from ongoing operations after income taxes, but before equity in undistributed income of subsidiaries and extraordinary items.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_NetIncomeLossFromContinuingOperationsBeforeEquityInUndistributedIncomeOfSubsidiaries" xlink:href="sigi-20211231.xsd#sigi_NetIncomeLossFromContinuingOperationsBeforeEquityInUndistributedIncomeOfSubsidiaries"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_NetIncomeLossFromContinuingOperationsBeforeEquityInUndistributedIncomeOfSubsidiaries" xlink:to="lab_sigi_NetIncomeLossFromContinuingOperationsBeforeEquityInUndistributedIncomeOfSubsidiaries" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_PremiumsWrittenNetConsolidatedAbstract_07da857c-1f1c-4515-b854-e4d4c1d57d54_terseLabel_en-US" xlink:label="lab_us-gaap_PremiumsWrittenNetConsolidatedAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Premiums Written:</link:label>
    <link:label id="lab_us-gaap_PremiumsWrittenNetConsolidatedAbstract_label_en-US" xlink:label="lab_us-gaap_PremiumsWrittenNetConsolidatedAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Premiums Written, Net [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PremiumsWrittenNetConsolidatedAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PremiumsWrittenNetConsolidatedAbstract"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PremiumsWrittenNetConsolidatedAbstract" xlink:to="lab_us-gaap_PremiumsWrittenNetConsolidatedAbstract" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax_bae42e89-7af0-4989-be88-7b3c6efc60c6_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Unrealized holding (losses) gains during the period, Tax</link:label>
    <link:label id="lab_us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax_label_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">OCI, Debt Securities, Available-for-Sale, Unrealized Holding Gain (Loss), before Adjustment, Tax</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax" xlink:to="lab_us-gaap_OtherComprehensiveIncomeUnrealizedHoldingGainLossOnSecuritiesArisingDuringPeriodTax" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_CreditRatingAMBestDomain_8b25e9a9-226e-47ea-971d-8b01f0bea7ad_terseLabel_en-US" xlink:label="lab_srt_CreditRatingAMBestDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Credit Rating, AM Best [Domain]</link:label>
    <link:label id="lab_srt_CreditRatingAMBestDomain_label_en-US" xlink:label="lab_srt_CreditRatingAMBestDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Credit Rating, AM Best [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_CreditRatingAMBestDomain" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_CreditRatingAMBestDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_CreditRatingAMBestDomain" xlink:to="lab_srt_CreditRatingAMBestDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_NonCreditPortionofOtherThanTemporaryImpairmentsRecognizedinOtherComprehensiveIncomeGross_397d74c8-7645-4e9c-b650-17b814cbdf74_terseLabel_en-US" xlink:label="lab_sigi_NonCreditPortionofOtherThanTemporaryImpairmentsRecognizedinOtherComprehensiveIncomeGross" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Unrealized losses on securities with credit loss recognized in earnings; Gross</link:label>
    <link:label id="lab_sigi_NonCreditPortionofOtherThanTemporaryImpairmentsRecognizedinOtherComprehensiveIncomeGross_label_en-US" xlink:label="lab_sigi_NonCreditPortionofOtherThanTemporaryImpairmentsRecognizedinOtherComprehensiveIncomeGross" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Non-Credit Portion of Other-Than-Temporary Impairments Recognized in Other Comprehensive Income; Gross</link:label>
    <link:label id="lab_sigi_NonCreditPortionofOtherThanTemporaryImpairmentsRecognizedinOtherComprehensiveIncomeGross_documentation_en-US" xlink:label="lab_sigi_NonCreditPortionofOtherThanTemporaryImpairmentsRecognizedinOtherComprehensiveIncomeGross" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Non-credit portion of current other-than-temporary impairment losses on fixed maturity securities recognized in other comprehensive income pre tax. This item does not include changes in appreciation or loss in value.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_NonCreditPortionofOtherThanTemporaryImpairmentsRecognizedinOtherComprehensiveIncomeGross" xlink:href="sigi-20211231.xsd#sigi_NonCreditPortionofOtherThanTemporaryImpairmentsRecognizedinOtherComprehensiveIncomeGross"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_NonCreditPortionofOtherThanTemporaryImpairmentsRecognizedinOtherComprehensiveIncomeGross" xlink:to="lab_sigi_NonCreditPortionofOtherThanTemporaryImpairmentsRecognizedinOtherComprehensiveIncomeGross" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_CasualtyInsuranceProductLineMember_b47de0e0-8aca-4d6f-9648-51dc393226e9_terseLabel_en-US" xlink:label="lab_sigi_CasualtyInsuranceProductLineMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Casualty Insurance Product Line [Member]</link:label>
    <link:label id="lab_sigi_CasualtyInsuranceProductLineMember_label_en-US" xlink:label="lab_sigi_CasualtyInsuranceProductLineMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Casualty Insurance Product Line [Member]</link:label>
    <link:label id="lab_sigi_CasualtyInsuranceProductLineMember_documentation_en-US" xlink:label="lab_sigi_CasualtyInsuranceProductLineMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Product line consisting of casualty-related insurance.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_CasualtyInsuranceProductLineMember" xlink:href="sigi-20211231.xsd#sigi_CasualtyInsuranceProductLineMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_CasualtyInsuranceProductLineMember" xlink:to="lab_sigi_CasualtyInsuranceProductLineMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FinancialInstrumentAxis_17e8a1c4-51a6-42d6-8654-863fb5aa0c7b_terseLabel_en-US" xlink:label="lab_us-gaap_FinancialInstrumentAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Financial Instrument [Axis]</link:label>
    <link:label id="lab_us-gaap_FinancialInstrumentAxis_label_en-US" xlink:label="lab_us-gaap_FinancialInstrumentAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Financial Instrument [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinancialInstrumentAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinancialInstrumentAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FinancialInstrumentAxis" xlink:to="lab_us-gaap_FinancialInstrumentAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_AllowanceforCreditLossesAxis_0c521467-9daa-4a83-b0a9-158c74157505_terseLabel_en-US" xlink:label="lab_sigi_AllowanceforCreditLossesAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Allowance for Credit Losses [Axis]</link:label>
    <link:label id="lab_sigi_AllowanceforCreditLossesAxis_label_en-US" xlink:label="lab_sigi_AllowanceforCreditLossesAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Allowance for Credit Losses [Axis]</link:label>
    <link:label id="lab_sigi_AllowanceforCreditLossesAxis_documentation_en-US" xlink:label="lab_sigi_AllowanceforCreditLossesAxis" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Transaction types of credit losses incurred during the period.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_AllowanceforCreditLossesAxis" xlink:href="sigi-20211231.xsd#sigi_AllowanceforCreditLossesAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_AllowanceforCreditLossesAxis" xlink:to="lab_sigi_AllowanceforCreditLossesAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FinanceLeaseLiabilityUndiscountedExcessAmount_6ce5b46e-3968-44c9-967b-c74b3c6f53b4_terseLabel_en-US" xlink:label="lab_us-gaap_FinanceLeaseLiabilityUndiscountedExcessAmount" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Finance Lease imputed interest</link:label>
    <link:label id="lab_us-gaap_FinanceLeaseLiabilityUndiscountedExcessAmount_label_en-US" xlink:label="lab_us-gaap_FinanceLeaseLiabilityUndiscountedExcessAmount" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Finance Lease, Liability, Undiscounted Excess Amount</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseLiabilityUndiscountedExcessAmount" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinanceLeaseLiabilityUndiscountedExcessAmount"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FinanceLeaseLiabilityUndiscountedExcessAmount" xlink:to="lab_us-gaap_FinanceLeaseLiabilityUndiscountedExcessAmount" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ReinsuranceRecoverablesAllowance_e4550984-718e-45d6-805f-94845e471a25_negatedLabel_en-US" xlink:label="lab_us-gaap_ReinsuranceRecoverablesAllowance" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Reinsurance Recoverable, Allowance for Credit Loss</link:label>
    <link:label id="lab_us-gaap_ReinsuranceRecoverablesAllowance_15b6c140-c201-4d5c-93e4-efa0a504171c_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_ReinsuranceRecoverablesAllowance" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Reinsurance Recoverable, Allowance for Credit Loss</link:label>
    <link:label id="lab_us-gaap_ReinsuranceRecoverablesAllowance_fa29e99b-6b86-474c-9467-f2b0c1353f22_periodStartLabel_en-US" xlink:label="lab_us-gaap_ReinsuranceRecoverablesAllowance" xlink:role="http://www.xbrl.org/2003/role/periodStartLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Reinsurance Recoverable, Allowance for Credit Loss, Beginning Balance</link:label>
    <link:label id="lab_us-gaap_ReinsuranceRecoverablesAllowance_1a78a378-d12b-479f-9c05-5a3e0fd824d8_periodEndLabel_en-US" xlink:label="lab_us-gaap_ReinsuranceRecoverablesAllowance" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Reinsurance Recoverable, Allowance for Credit Loss, Ending Balance</link:label>
    <link:label id="lab_us-gaap_ReinsuranceRecoverablesAllowance_label_en-US" xlink:label="lab_us-gaap_ReinsuranceRecoverablesAllowance" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Reinsurance Recoverable, Allowance for Credit Loss</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReinsuranceRecoverablesAllowance" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ReinsuranceRecoverablesAllowance"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ReinsuranceRecoverablesAllowance" xlink:to="lab_us-gaap_ReinsuranceRecoverablesAllowance" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_DebtSecuritiesHeldToMaturityAllowanceForCreditLoss_0b70dcc2-aa5b-4818-a0f2-010913ede46b_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_DebtSecuritiesHeldToMaturityAllowanceForCreditLoss" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Fixed Income Securities, Held-to-maturity, Allowance for Credit Loss</link:label>
    <link:label id="lab_us-gaap_DebtSecuritiesHeldToMaturityAllowanceForCreditLoss_label_en-US" xlink:label="lab_us-gaap_DebtSecuritiesHeldToMaturityAllowanceForCreditLoss" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Debt Securities, Held-to-maturity, Allowance for Credit Loss</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_DebtSecuritiesHeldToMaturityAllowanceForCreditLoss" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_DebtSecuritiesHeldToMaturityAllowanceForCreditLoss"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DebtSecuritiesHeldToMaturityAllowanceForCreditLoss" xlink:to="lab_us-gaap_DebtSecuritiesHeldToMaturityAllowanceForCreditLoss" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_EnvironmentalclaimsMember_5246389d-6615-412b-9c6d-8027d3b4d35a_terseLabel_en-US" xlink:label="lab_sigi_EnvironmentalclaimsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Enviromental [Member]</link:label>
    <link:label id="lab_sigi_EnvironmentalclaimsMember_label_en-US" xlink:label="lab_sigi_EnvironmentalclaimsMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">EnvironmentalClaims [Member]</link:label>
    <link:label id="lab_sigi_EnvironmentalclaimsMember_documentation_en-US" xlink:label="lab_sigi_EnvironmentalclaimsMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Represents non-asbestos environmental related claims.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_EnvironmentalclaimsMember" xlink:href="sigi-20211231.xsd#sigi_EnvironmentalclaimsMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_EnvironmentalclaimsMember" xlink:to="lab_sigi_EnvironmentalclaimsMember" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_AllOtherReinsurersMember_225549c8-be90-434e-9520-d5f58b0f134b_terseLabel_en-US" xlink:label="lab_sigi_AllOtherReinsurersMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">All Other Reinsurers [Member]</link:label>
    <link:label id="lab_sigi_AllOtherReinsurersMember_label_en-US" xlink:label="lab_sigi_AllOtherReinsurersMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">All Other Reinsurers [Member]</link:label>
    <link:label id="lab_sigi_AllOtherReinsurersMember_documentation_en-US" xlink:label="lab_sigi_AllOtherReinsurersMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Represents all other reinsurers not otherwise mentioned.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_AllOtherReinsurersMember" xlink:href="sigi-20211231.xsd#sigi_AllOtherReinsurersMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_AllOtherReinsurersMember" xlink:to="lab_sigi_AllOtherReinsurersMember" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_RemainingCommitment_8110632b-667c-4bf2-b48a-98e8e039e1b0_terseLabel_en-US" xlink:label="lab_sigi_RemainingCommitment" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Remaining Commitment</link:label>
    <link:label id="lab_sigi_RemainingCommitment_label_en-US" xlink:label="lab_sigi_RemainingCommitment" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Remaining Commitment</link:label>
    <link:label id="lab_sigi_RemainingCommitment_documentation_en-US" xlink:label="lab_sigi_RemainingCommitment" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">This item represents contractual obligations to invest additional amounts on our other investment portfolio. These additional investments may or may not be required.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_RemainingCommitment" xlink:href="sigi-20211231.xsd#sigi_RemainingCommitment"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_RemainingCommitment" xlink:to="lab_sigi_RemainingCommitment" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_Cashandinvestmentsheldatparent_8b0dc350-8813-486f-9220-78db90b3373c_terseLabel_en-US" xlink:label="lab_sigi_Cashandinvestmentsheldatparent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Investments and Cash Available to fund future dividend and interest payments</link:label>
    <link:label id="lab_sigi_Cashandinvestmentsheldatparent_label_en-US" xlink:label="lab_sigi_Cashandinvestmentsheldatparent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Cash and investments held at parent</link:label>
    <link:label id="lab_sigi_Cashandinvestmentsheldatparent_documentation_en-US" xlink:label="lab_sigi_Cashandinvestmentsheldatparent" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Amount of cash and investments held at the Parent company</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_Cashandinvestmentsheldatparent" xlink:href="sigi-20211231.xsd#sigi_Cashandinvestmentsheldatparent"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_Cashandinvestmentsheldatparent" xlink:to="lab_sigi_Cashandinvestmentsheldatparent" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_DocumentInformationTable_3628393c-bb11-4246-b4b5-ffb6bcfb2a57_terseLabel_en-US" xlink:label="lab_dei_DocumentInformationTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Document Information [Table]</link:label>
    <link:label id="lab_dei_DocumentInformationTable_label_en-US" xlink:label="lab_dei_DocumentInformationTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Document Information [Table]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentInformationTable" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_DocumentInformationTable"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_DocumentInformationTable" xlink:to="lab_dei_DocumentInformationTable" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_CarryingReportedAmountFairValueDisclosureMember_493c0745-923f-42e9-9295-bcf33a89c601_terseLabel_en-US" xlink:label="lab_us-gaap_CarryingReportedAmountFairValueDisclosureMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Carrying Amount [Member]</link:label>
    <link:label id="lab_us-gaap_CarryingReportedAmountFairValueDisclosureMember_label_en-US" xlink:label="lab_us-gaap_CarryingReportedAmountFairValueDisclosureMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Reported Value Measurement [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CarryingReportedAmountFairValueDisclosureMember" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CarryingReportedAmountFairValueDisclosureMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CarryingReportedAmountFairValueDisclosureMember" xlink:to="lab_us-gaap_CarryingReportedAmountFairValueDisclosureMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ScheduleOfCausesOfIncreaseDecreaseInLiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseTextBlock_739b175e-c4a5-48f6-9ef6-a51e958d21a7_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfCausesOfIncreaseDecreaseInLiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule of (Favorable)/ Unfavorable Prior Year Development</link:label>
    <link:label id="lab_us-gaap_ScheduleOfCausesOfIncreaseDecreaseInLiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfCausesOfIncreaseDecreaseInLiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule of Causes of Increase (Decrease) in Liability for Unpaid Claims and Claims Adjustment Expense [Table Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfCausesOfIncreaseDecreaseInLiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfCausesOfIncreaseDecreaseInLiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfCausesOfIncreaseDecreaseInLiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseTextBlock" xlink:to="lab_us-gaap_ScheduleOfCausesOfIncreaseDecreaseInLiabilityForUnpaidClaimsAndClaimsAdjustmentExpenseTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FinanceLeaseLiabilityPaymentsDueYearFive_eab27da6-0c9f-4d0b-b7bd-fd6fd7abd48a_terseLabel_en-US" xlink:label="lab_us-gaap_FinanceLeaseLiabilityPaymentsDueYearFive" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Finance Lease Liability, Due Year Five</link:label>
    <link:label id="lab_us-gaap_FinanceLeaseLiabilityPaymentsDueYearFive_label_en-US" xlink:label="lab_us-gaap_FinanceLeaseLiabilityPaymentsDueYearFive" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Finance Lease, Liability, to be Paid, Year Five</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FinanceLeaseLiabilityPaymentsDueYearFive" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FinanceLeaseLiabilityPaymentsDueYearFive"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FinanceLeaseLiabilityPaymentsDueYearFive" xlink:to="lab_us-gaap_FinanceLeaseLiabilityPaymentsDueYearFive" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_CommonStockMember_b91bf2bd-058c-4dfd-86cf-d7094fa3e5e7_terseLabel_en-US" xlink:label="lab_us-gaap_CommonStockMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Common Stock [Member]</link:label>
    <link:label id="lab_us-gaap_CommonStockMember_da62e7bd-5356-4412-b8f1-d8b5d1f1874e_verboseLabel_en-US" xlink:label="lab_us-gaap_CommonStockMember" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Non-publicly traded common stock within our equity portfolio</link:label>
    <link:label id="lab_us-gaap_CommonStockMember_label_en-US" xlink:label="lab_us-gaap_CommonStockMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Common Stock [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_CommonStockMember" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_CommonStockMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_CommonStockMember" xlink:to="lab_us-gaap_CommonStockMember" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_PrivateCreditFundsMember_b3a8c3f5-a80a-42e3-aa67-0c236510da8c_terseLabel_en-US" xlink:label="lab_sigi_PrivateCreditFundsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Private Credit Funds [Member]</link:label>
    <link:label id="lab_sigi_PrivateCreditFundsMember_label_en-US" xlink:label="lab_sigi_PrivateCreditFundsMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Private Credit Funds [Member]</link:label>
    <link:label id="lab_sigi_PrivateCreditFundsMember_documentation_en-US" xlink:label="lab_sigi_PrivateCreditFundsMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">This strategy includes the Mezzanine Financing and Distressed Debt strategies, providing privately negotiated fixed income securities, generally with an equity component, to LBO firms and private and publicly traded large, mid and small-cap companies to finance LBOs, recapitalizations, and acquisitions, and making direct and indirect investments in debt and equity securities of companies that are experiencing financial and/or operational distress.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_PrivateCreditFundsMember" xlink:href="sigi-20211231.xsd#sigi_PrivateCreditFundsMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_PrivateCreditFundsMember" xlink:to="lab_sigi_PrivateCreditFundsMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_EquityMethodInvestmentNonconsolidatedInvesteeOtherMember_fe93d048-56f1-4c90-a82d-8d0e77f54531_terseLabel_en-US" xlink:label="lab_us-gaap_EquityMethodInvestmentNonconsolidatedInvesteeOtherMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Equity Method Investment, Nonconsolidated Investee, Other</link:label>
    <link:label id="lab_us-gaap_EquityMethodInvestmentNonconsolidatedInvesteeOtherMember_label_en-US" xlink:label="lab_us-gaap_EquityMethodInvestmentNonconsolidatedInvesteeOtherMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Equity Method Investment, Nonconsolidated Investee, Other [Member]</link:label>
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    <link:label id="lab_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment_133bacf6-9354-4777-adb1-494f1a3d60e8_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_PaymentsToAcquirePropertyPlantAndEquipment" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Purchase of property and equipment</link:label>
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    <link:label id="lab_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain_8eda70b8-b41a-4c3a-a073-b6b1c0d04dbf_terseLabel_en-US" xlink:label="lab_us-gaap_ShortdurationInsuranceContractsAccidentYearDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Short-duration Insurance Contracts, Accident Year [Domain]</link:label>
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    <link:label id="lab_us-gaap_ValuationTechniqueAxis_6ddda9f8-7380-4ac4-ba8f-495432cf62fb_terseLabel_en-US" xlink:label="lab_us-gaap_ValuationTechniqueAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Valuation Approach and Technique [Axis]</link:label>
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    <link:label id="lab_us-gaap_PropertyLiabilityAndCasualtyInsuranceSegmentMember_426637a7-d532-4fb4-939c-534fd7f7b2c0_verboseLabel_en-US" xlink:label="lab_us-gaap_PropertyLiabilityAndCasualtyInsuranceSegmentMember" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Property and liability insurance [Member]</link:label>
    <link:label id="lab_us-gaap_PropertyLiabilityAndCasualtyInsuranceSegmentMember_label_en-US" xlink:label="lab_us-gaap_PropertyLiabilityAndCasualtyInsuranceSegmentMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Property, Liability and Casualty Insurance Product Line [Member]</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_PurchaseAmountOfAnnuities" xlink:to="lab_sigi_PurchaseAmountOfAnnuities" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_LiabilityForAsbestosAndEnvironmentalClaimsNetPaymentForClaimsSIGI_9883468f-1767-4f83-b7a3-fc7efcbd3874_terseLabel_en-US" xlink:label="lab_sigi_LiabilityForAsbestosAndEnvironmentalClaimsNetPaymentForClaimsSIGI" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Less: loss and loss expense paid, Net</link:label>
    <link:label id="lab_sigi_LiabilityForAsbestosAndEnvironmentalClaimsNetPaymentForClaimsSIGI_label_en-US" xlink:label="lab_sigi_LiabilityForAsbestosAndEnvironmentalClaimsNetPaymentForClaimsSIGI" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Liability For Asbestos And Environmental Claims Net Payment For Claims SIGI</link:label>
    <link:label id="lab_sigi_LiabilityForAsbestosAndEnvironmentalClaimsNetPaymentForClaimsSIGI_documentation_en-US" xlink:label="lab_sigi_LiabilityForAsbestosAndEnvironmentalClaimsNetPaymentForClaimsSIGI" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Amount, after effects of reinsurance, of payments to settle insured claims and pay costs incurred in the claims settlement process attributable to asbestos and environmental claims.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_LiabilityForAsbestosAndEnvironmentalClaimsNetPaymentForClaimsSIGI" xlink:href="sigi-20211231.xsd#sigi_LiabilityForAsbestosAndEnvironmentalClaimsNetPaymentForClaimsSIGI"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_LiabilityForAsbestosAndEnvironmentalClaimsNetPaymentForClaimsSIGI" xlink:to="lab_sigi_LiabilityForAsbestosAndEnvironmentalClaimsNetPaymentForClaimsSIGI" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_AllowanceForLoanAndLeaseLossesRealEstate_e14c7064-c9af-49d0-b8c3-4baedcb66f62_terseLabel_en-US" xlink:label="lab_us-gaap_AllowanceForLoanAndLeaseLossesRealEstate" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Commercial mortgage loans, Allowance for Credit Loss</link:label>
    <link:label id="lab_us-gaap_AllowanceForLoanAndLeaseLossesRealEstate_label_en-US" xlink:label="lab_us-gaap_AllowanceForLoanAndLeaseLossesRealEstate" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Allowance for Loan and Lease Losses, Real Estate</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_AllowanceForLoanAndLeaseLossesRealEstate" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_AllowanceForLoanAndLeaseLossesRealEstate"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AllowanceForLoanAndLeaseLossesRealEstate" xlink:to="lab_us-gaap_AllowanceForLoanAndLeaseLossesRealEstate" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_ReinsuranceRecoverableforPaidandUnpaidClaimsandClaimsAdjustmentsGrossMember_6643eab5-6d71-4615-bf63-f5d74c9d20ba_terseLabel_en-US" xlink:label="lab_sigi_ReinsuranceRecoverableforPaidandUnpaidClaimsandClaimsAdjustmentsGrossMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Reinsurance Recoverable for Paid and Unpaid Claims and Claims Adjustments, Gross [Member]</link:label>
    <link:label id="lab_sigi_ReinsuranceRecoverableforPaidandUnpaidClaimsandClaimsAdjustmentsGrossMember_label_en-US" xlink:label="lab_sigi_ReinsuranceRecoverableforPaidandUnpaidClaimsandClaimsAdjustmentsGrossMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Reinsurance Recoverable for Paid and Unpaid Claims and Claims Adjustments, Gross [Member]</link:label>
    <link:label id="lab_sigi_ReinsuranceRecoverableforPaidandUnpaidClaimsandClaimsAdjustmentsGrossMember_documentation_en-US" xlink:label="lab_sigi_ReinsuranceRecoverableforPaidandUnpaidClaimsandClaimsAdjustmentsGrossMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Reinsurance recoverable for unpaid claims and claims adjustments prior to the unpaid claims allowance.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_ReinsuranceRecoverableforPaidandUnpaidClaimsandClaimsAdjustmentsGrossMember" xlink:href="sigi-20211231.xsd#sigi_ReinsuranceRecoverableforPaidandUnpaidClaimsandClaimsAdjustmentsGrossMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_ReinsuranceRecoverableforPaidandUnpaidClaimsandClaimsAdjustmentsGrossMember" xlink:to="lab_sigi_ReinsuranceRecoverableforPaidandUnpaidClaimsandClaimsAdjustmentsGrossMember" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_LongTermDebtExcludingIssuanceCostsMember_274e4e6a-45c8-4240-991f-8c401f24c027_terseLabel_en-US" xlink:label="lab_sigi_LongTermDebtExcludingIssuanceCostsMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Long Term Debt Excluding Issuance Costs [Member]</link:label>
    <link:label id="lab_sigi_LongTermDebtExcludingIssuanceCostsMember_label_en-US" xlink:label="lab_sigi_LongTermDebtExcludingIssuanceCostsMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Long Term Debt Excluding Issuance Costs [Member]</link:label>
    <link:label id="lab_sigi_LongTermDebtExcludingIssuanceCostsMember_documentation_en-US" xlink:label="lab_sigi_LongTermDebtExcludingIssuanceCostsMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Debt arrangement having an initial term longer than one year or beyond the normal operating cycle, if longer excluding related debt issuance costs.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_LongTermDebtExcludingIssuanceCostsMember" xlink:href="sigi-20211231.xsd#sigi_LongTermDebtExcludingIssuanceCostsMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_LongTermDebtExcludingIssuanceCostsMember" xlink:to="lab_sigi_LongTermDebtExcludingIssuanceCostsMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentBeforeTax_dc6a8816-a412-4155-93d6-3c67ee2bce56_negatedTotalLabel_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentBeforeTax" xlink:role="http://www.xbrl.org/2009/role/negatedTotalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Defined pension and other post-retirement benefit plans, Gross</link:label>
    <link:label id="lab_us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentBeforeTax_label_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentBeforeTax" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, before Tax</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentBeforeTax" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentBeforeTax"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentBeforeTax" xlink:to="lab_us-gaap_OtherComprehensiveIncomeLossPensionAndOtherPostretirementBenefitPlansAdjustmentBeforeTax" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_InvestmentHoldingsTable_6d57fff0-63e9-45eb-9dbf-3e6822b4218c_terseLabel_en-US" xlink:label="lab_us-gaap_InvestmentHoldingsTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Investment Holdings [Table]</link:label>
    <link:label id="lab_us-gaap_InvestmentHoldingsTable_label_en-US" xlink:label="lab_us-gaap_InvestmentHoldingsTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Investment Holdings [Table]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentHoldingsTable" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InvestmentHoldingsTable"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_InvestmentHoldingsTable" xlink:to="lab_us-gaap_InvestmentHoldingsTable" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ScheduleOfAssumptionsUsedTableTextBlock_c60d3246-427b-407c-b385-a4223728ef35_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfAssumptionsUsedTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule Of Weighted- Average Expense and Liability Assumptions</link:label>
    <link:label id="lab_us-gaap_ScheduleOfAssumptionsUsedTableTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfAssumptionsUsedTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Defined Benefit Plan, Assumptions [Table Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAssumptionsUsedTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfAssumptionsUsedTableTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfAssumptionsUsedTableTextBlock" xlink:to="lab_us-gaap_ScheduleOfAssumptionsUsedTableTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_EntityAddressCityOrTown_83ed5e49-5151-41e7-9e74-ae5692eb604a_terseLabel_en-US" xlink:label="lab_dei_EntityAddressCityOrTown" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Entity Address, City or Town</link:label>
    <link:label id="lab_dei_EntityAddressCityOrTown_label_en-US" xlink:label="lab_dei_EntityAddressCityOrTown" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Entity Address, City or Town</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityAddressCityOrTown" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityAddressCityOrTown"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_EntityAddressCityOrTown" xlink:to="lab_dei_EntityAddressCityOrTown" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_RegulatoryCapitalEventMember_e5952ea6-c468-4a17-a9c3-679cf4cebdc5_terseLabel_en-US" xlink:label="lab_sigi_RegulatoryCapitalEventMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Regulatory Capital Event [Member]</link:label>
    <link:label id="lab_sigi_RegulatoryCapitalEventMember_label_en-US" xlink:label="lab_sigi_RegulatoryCapitalEventMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Regulatory Capital Event [Member]</link:label>
    <link:label id="lab_sigi_RegulatoryCapitalEventMember_documentation_en-US" xlink:label="lab_sigi_RegulatoryCapitalEventMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">The price per share at which the preferred stock of an entity that has priority over common stock in the distribution of dividends and in the event of liquidation of the entity is redeemed or may be called at in the event of a regulatory agency event where a regulatory agency changes its criteria used to assign equity credit to securities like the Preferred Stock.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_RegulatoryCapitalEventMember" xlink:href="sigi-20211231.xsd#sigi_RegulatoryCapitalEventMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_RegulatoryCapitalEventMember" xlink:to="lab_sigi_RegulatoryCapitalEventMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ScheduleOfExpectedBenefitPaymentsTableTextBlock_602455f9-bd38-4174-b420-763a8e14dd70_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfExpectedBenefitPaymentsTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule of Expected Benefit Payments</link:label>
    <link:label id="lab_us-gaap_ScheduleOfExpectedBenefitPaymentsTableTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfExpectedBenefitPaymentsTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule of Expected Benefit Payments [Table Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfExpectedBenefitPaymentsTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfExpectedBenefitPaymentsTableTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfExpectedBenefitPaymentsTableTextBlock" xlink:to="lab_us-gaap_ScheduleOfExpectedBenefitPaymentsTableTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ScheduleOfAccumulatedOtherComprehensiveIncomeLossTableTextBlock_c9659288-ebb0-4c79-a9b1-fe3e4009720c_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfAccumulatedOtherComprehensiveIncomeLossTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule of Components of Accumulated Other Comprehensive Income</link:label>
    <link:label id="lab_us-gaap_ScheduleOfAccumulatedOtherComprehensiveIncomeLossTableTextBlock_label_en-US" xlink:label="lab_us-gaap_ScheduleOfAccumulatedOtherComprehensiveIncomeLossTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ScheduleOfAccumulatedOtherComprehensiveIncomeLossTableTextBlock" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ScheduleOfAccumulatedOtherComprehensiveIncomeLossTableTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfAccumulatedOtherComprehensiveIncomeLossTableTextBlock" xlink:to="lab_us-gaap_ScheduleOfAccumulatedOtherComprehensiveIncomeLossTableTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_RetirementPlanTypeAxis_db798aae-f3e1-4625-b128-58d370dcac92_terseLabel_en-US" xlink:label="lab_us-gaap_RetirementPlanTypeAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Retirement Plan Type [Axis]</link:label>
    <link:label id="lab_us-gaap_RetirementPlanTypeAxis_label_en-US" xlink:label="lab_us-gaap_RetirementPlanTypeAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Retirement Plan Type [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_RetirementPlanTypeAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_RetirementPlanTypeAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RetirementPlanTypeAxis" xlink:to="lab_us-gaap_RetirementPlanTypeAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_PremiumsReceivableAllowanceNetOfWriteoffs_50aee6fd-e2b0-4b4e-a4cf-a3d37ae34f1d_terseLabel_en-US" xlink:label="lab_sigi_PremiumsReceivableAllowanceNetOfWriteoffs" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Allowance for credit losses, net of write-offs</link:label>
    <link:label id="lab_sigi_PremiumsReceivableAllowanceNetOfWriteoffs_label_en-US" xlink:label="lab_sigi_PremiumsReceivableAllowanceNetOfWriteoffs" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Premiums receivable allowance net of writeoffs</link:label>
    <link:label id="lab_sigi_PremiumsReceivableAllowanceNetOfWriteoffs_documentation_en-US" xlink:label="lab_sigi_PremiumsReceivableAllowanceNetOfWriteoffs" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">The amount of allowance for credit losses in the period presented less write-offs that were charged against the allowance.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_PremiumsReceivableAllowanceNetOfWriteoffs" xlink:href="sigi-20211231.xsd#sigi_PremiumsReceivableAllowanceNetOfWriteoffs"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_PremiumsReceivableAllowanceNetOfWriteoffs" xlink:to="lab_sigi_PremiumsReceivableAllowanceNetOfWriteoffs" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_BalanceSheetLocationAxis_d2c08e96-c0f7-4188-b7c9-deca89632c50_terseLabel_en-US" xlink:label="lab_us-gaap_BalanceSheetLocationAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Balance Sheet Location [Axis]</link:label>
    <link:label id="lab_us-gaap_BalanceSheetLocationAxis_label_en-US" xlink:label="lab_us-gaap_BalanceSheetLocationAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Balance Sheet Location [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_BalanceSheetLocationAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_BalanceSheetLocationAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_BalanceSheetLocationAxis" xlink:to="lab_us-gaap_BalanceSheetLocationAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_FederalHomeLoanBankOfIndianapolisMember_6009be25-c480-422a-8124-d59019049287_terseLabel_en-US" xlink:label="lab_srt_FederalHomeLoanBankOfIndianapolisMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Federal Home Loan Bank of Indianapolis [Member]</link:label>
    <link:label id="lab_srt_FederalHomeLoanBankOfIndianapolisMember_label_en-US" xlink:label="lab_srt_FederalHomeLoanBankOfIndianapolisMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Federal Home Loan Bank of Indianapolis [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_FederalHomeLoanBankOfIndianapolisMember" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_FederalHomeLoanBankOfIndianapolisMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_FederalHomeLoanBankOfIndianapolisMember" xlink:to="lab_srt_FederalHomeLoanBankOfIndianapolisMember" xlink:type="arc" order="1"/>
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    <link:label id="lab_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSettlements_8e7e3259-e3ed-42e6-b400-e2938b6f2eeb_terseLabel_en-US" xlink:label="lab_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSettlements" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Settlements</link:label>
    <link:label id="lab_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSettlements_label_en-US" xlink:label="lab_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSettlements" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Settlements</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSettlements" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSettlements"/>
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    <link:label id="lab_us-gaap_IncreaseDecreaseInIncomeTaxes_2322f64a-6858-4ddb-ab0c-d959d1560298_terseLabel_en-US" xlink:label="lab_us-gaap_IncreaseDecreaseInIncomeTaxes" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">(Increase) decrease in net federal income taxes</link:label>
    <link:label id="lab_us-gaap_IncreaseDecreaseInIncomeTaxes_b7e9d9a2-db57-42a6-9dfe-ac238fe7cfa8_verboseLabel_en-US" xlink:label="lab_us-gaap_IncreaseDecreaseInIncomeTaxes" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Decrease in net federal income taxes</link:label>
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    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncreaseDecreaseInIncomeTaxes" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncreaseDecreaseInIncomeTaxes"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncreaseDecreaseInIncomeTaxes" xlink:to="lab_us-gaap_IncreaseDecreaseInIncomeTaxes" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_ProductOrServiceAxis_6cb0ba82-a47e-4600-bf48-66b5ea90f906_terseLabel_en-US" xlink:label="lab_srt_ProductOrServiceAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Line of Business [Axis]</link:label>
    <link:label id="lab_srt_ProductOrServiceAxis_d1220b9a-913b-4a70-9e6e-8aac36312742_verboseLabel_en-US" xlink:label="lab_srt_ProductOrServiceAxis" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Reinsurance Premiums for Insurance Companies, by Product Segment [Axis]</link:label>
    <link:label id="lab_srt_ProductOrServiceAxis_label_en-US" xlink:label="lab_srt_ProductOrServiceAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Product and Service [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ProductOrServiceAxis" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ProductOrServiceAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_ProductOrServiceAxis" xlink:to="lab_srt_ProductOrServiceAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_PreferredStockParOrStatedValuePerShare_2966ed81-809e-411e-8922-049798fd4035_terseLabel_en-US" xlink:label="lab_us-gaap_PreferredStockParOrStatedValuePerShare" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Preferred Stock, Par or Stated Value (in dollars per share)</link:label>
    <link:label id="lab_us-gaap_PreferredStockParOrStatedValuePerShare_label_en-US" xlink:label="lab_us-gaap_PreferredStockParOrStatedValuePerShare" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Preferred Stock, Par or Stated Value Per Share</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PreferredStockParOrStatedValuePerShare" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PreferredStockParOrStatedValuePerShare"/>
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    <link:label id="lab_dei_EntityPublicFloat_ebc0409a-7caf-409a-ac5b-d8afe2b1fa34_terseLabel_en-US" xlink:label="lab_dei_EntityPublicFloat" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Entity Public Float</link:label>
    <link:label id="lab_dei_EntityPublicFloat_label_en-US" xlink:label="lab_dei_EntityPublicFloat" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Entity Public Float</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_EntityPublicFloat" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_EntityPublicFloat"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_EntityPublicFloat" xlink:to="lab_dei_EntityPublicFloat" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_DocumentsIncorporatedByReferenceTextBlock_c76b3f8f-847d-4e0a-9671-73dc27e9e8c7_terseLabel_en-US" xlink:label="lab_dei_DocumentsIncorporatedByReferenceTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Documents Incorporated by Reference</link:label>
    <link:label id="lab_dei_DocumentsIncorporatedByReferenceTextBlock_label_en-US" xlink:label="lab_dei_DocumentsIncorporatedByReferenceTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Documents Incorporated by Reference [Text Block]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentsIncorporatedByReferenceTextBlock" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_DocumentsIncorporatedByReferenceTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_DocumentsIncorporatedByReferenceTextBlock" xlink:to="lab_dei_DocumentsIncorporatedByReferenceTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_MaximumBorrowingPercentage_2e324a07-1209-4538-9e38-9d1a1889a7ae_terseLabel_en-US" xlink:label="lab_sigi_MaximumBorrowingPercentage" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Maximum borrowing percentage</link:label>
    <link:label id="lab_sigi_MaximumBorrowingPercentage_label_en-US" xlink:label="lab_sigi_MaximumBorrowingPercentage" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Maximum borrowing percentage</link:label>
    <link:label id="lab_sigi_MaximumBorrowingPercentage_documentation_en-US" xlink:label="lab_sigi_MaximumBorrowingPercentage" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">The maximum collaterized borrowing percentage from SISE and SISC admitted assets</link:label>
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    <link:label id="lab_sigi_OnePointSixtyOnePercentBorrowingFromFederalHomeLoanBankDueJuly212021Member_4ac8959c-a4cb-4b9d-899a-5695eb7715a5_terseLabel_en-US" xlink:label="lab_sigi_OnePointSixtyOnePercentBorrowingFromFederalHomeLoanBankDueJuly212021Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">One Point Sixty One Percent Borrowing From Federal Home Loan Bank Due July 21, 2021 [Member]</link:label>
    <link:label id="lab_sigi_OnePointSixtyOnePercentBorrowingFromFederalHomeLoanBankDueJuly212021Member_label_en-US" xlink:label="lab_sigi_OnePointSixtyOnePercentBorrowingFromFederalHomeLoanBankDueJuly212021Member" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">One Point Sixty One Percent Borrowing From Federal Home Loan Bank Due July 21, 2021 [Member]</link:label>
    <link:label id="lab_sigi_OnePointSixtyOnePercentBorrowingFromFederalHomeLoanBankDueJuly212021Member_documentation_en-US" xlink:label="lab_sigi_OnePointSixtyOnePercentBorrowingFromFederalHomeLoanBankDueJuly212021Member" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">One Point Sixty One Percent Borrowing From Federal Home Loan Bank Due July 21, 2021</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_OnePointSixtyOnePercentBorrowingFromFederalHomeLoanBankDueJuly212021Member" xlink:href="sigi-20211231.xsd#sigi_OnePointSixtyOnePercentBorrowingFromFederalHomeLoanBankDueJuly212021Member"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_OnePointSixtyOnePercentBorrowingFromFederalHomeLoanBankDueJuly212021Member" xlink:to="lab_sigi_OnePointSixtyOnePercentBorrowingFromFederalHomeLoanBankDueJuly212021Member" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_SalvageAndSubrogationRecoveriesValue_c5cf441f-cd29-42e3-a47c-0832ceb44728_verboseLabel_en-US" xlink:label="lab_us-gaap_SalvageAndSubrogationRecoveriesValue" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Anticipated recoveries for salvage and subrogation claims</link:label>
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    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SalvageAndSubrogationRecoveriesValue" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SalvageAndSubrogationRecoveriesValue"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SalvageAndSubrogationRecoveriesValue" xlink:to="lab_us-gaap_SalvageAndSubrogationRecoveriesValue" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ShortTermLeaseCost_3ea718a2-5f8e-4276-8b5e-0de64aead51c_terseLabel_en-US" xlink:label="lab_us-gaap_ShortTermLeaseCost" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Short-term lease cost</link:label>
    <link:label id="lab_us-gaap_ShortTermLeaseCost_label_en-US" xlink:label="lab_us-gaap_ShortTermLeaseCost" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Short-term Lease, Cost</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShortTermLeaseCost" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShortTermLeaseCost"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShortTermLeaseCost" xlink:to="lab_us-gaap_ShortTermLeaseCost" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation_709b9f8b-8276-4f03-831a-f90655227654_terseLabel_en-US" xlink:label="lab_us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Stock purchase and compensation plan</link:label>
    <link:label id="lab_us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation_f2f19151-b624-4a2b-adc6-6abf4007088a_verboseLabel_en-US" xlink:label="lab_us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Stock Issued During Period Shares</link:label>
    <link:label id="lab_us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation_label_en-US" xlink:label="lab_us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Shares Issued, Shares, Share-based Payment Arrangement, after Forfeiture</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation" xlink:to="lab_us-gaap_StockIssuedDuringPeriodSharesShareBasedCompensation" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_AdditionalBorrowingCapacityForParent_30c2722b-60f5-4b18-8ae1-bdbd1eeef904_terseLabel_en-US" xlink:label="lab_sigi_AdditionalBorrowingCapacityForParent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Additional Borrowing Capacity for Parent</link:label>
    <link:label id="lab_sigi_AdditionalBorrowingCapacityForParent_label_en-US" xlink:label="lab_sigi_AdditionalBorrowingCapacityForParent" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Additional Borrowing Capacity for Parent</link:label>
    <link:label id="lab_sigi_AdditionalBorrowingCapacityForParent_documentation_en-US" xlink:label="lab_sigi_AdditionalBorrowingCapacityForParent" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">The additional borrowing capacity for the Parent from the Indiana Subsidiaries.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_AdditionalBorrowingCapacityForParent" xlink:href="sigi-20211231.xsd#sigi_AdditionalBorrowingCapacityForParent"/>
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    <link:label id="lab_sigi_TotalEquitiesMember_a03affd1-5acf-499b-9e83-270ac0f600d8_terseLabel_en-US" xlink:label="lab_sigi_TotalEquitiesMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Total Equities [Member]</link:label>
    <link:label id="lab_sigi_TotalEquitiesMember_label_en-US" xlink:label="lab_sigi_TotalEquitiesMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Total Equities [Member]</link:label>
    <link:label id="lab_sigi_TotalEquitiesMember_documentation_en-US" xlink:label="lab_sigi_TotalEquitiesMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Represents a group of securities that are constructed to have multi-asset exposure broadly diversified across asset classes, countries, sectors, as well as capitalization and credit spectrums.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_TotalEquitiesMember" xlink:href="sigi-20211231.xsd#sigi_TotalEquitiesMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_TotalEquitiesMember" xlink:to="lab_sigi_TotalEquitiesMember" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_PersonalAutomobileMember_eff48763-02ab-4f38-bc03-c8f589ae217e_terseLabel_en-US" xlink:label="lab_sigi_PersonalAutomobileMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Personal Automobile [Member]</link:label>
    <link:label id="lab_sigi_PersonalAutomobileMember_label_en-US" xlink:label="lab_sigi_PersonalAutomobileMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Personal Automobile [Member]</link:label>
    <link:label id="lab_sigi_PersonalAutomobileMember_documentation_en-US" xlink:label="lab_sigi_PersonalAutomobileMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Represents insurance coverage provided to policy holders on personal automobiles.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_PersonalAutomobileMember" xlink:href="sigi-20211231.xsd#sigi_PersonalAutomobileMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_PersonalAutomobileMember" xlink:to="lab_sigi_PersonalAutomobileMember" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_InvestmentsAbstract_d324ec67-037f-4267-be0d-bc47847dc2a5_terseLabel_en-US" xlink:label="lab_us-gaap_InvestmentsAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Investments [Abstract]</link:label>
    <link:label id="lab_us-gaap_InvestmentsAbstract_label_en-US" xlink:label="lab_us-gaap_InvestmentsAbstract" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Investments [Abstract]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_InvestmentsAbstract" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_InvestmentsAbstract"/>
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    <link:label id="lab_us-gaap_PropertyPlantAndEquipmentByTypeAxis_651cb748-6186-4638-a33d-45880e24a10a_terseLabel_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentByTypeAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Property, Plant and Equipment by Type [Axis]</link:label>
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    <link:label id="lab_sigi_UnrealizedGainLossOnInvestmentsDomain_589f7435-ecd3-409b-a1be-c64731de0cca_terseLabel_en-US" xlink:label="lab_sigi_UnrealizedGainLossOnInvestmentsDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Unrealized Gain Loss On Investments [Domain]</link:label>
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    <link:label id="lab_us-gaap_LinesOfCreditCurrent_6bcf2602-04d5-4679-ba12-4cf2bf7e40a8_terseLabel_en-US" xlink:label="lab_us-gaap_LinesOfCreditCurrent" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Line of Credit, Current</link:label>
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    <link:label id="lab_sigi_NewYorkDividendRestriction_fe155627-7fd3-46ba-a7b4-8ce99f09982f_terseLabel_en-US" xlink:label="lab_sigi_NewYorkDividendRestriction" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">New York Dividend Restriction on Insurer's Statutory Surplus</link:label>
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    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross" xlink:to="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsGrantsInPeriodGross" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_FairValueByAssetClassAxis_ae68ed58-6d73-40ca-86e6-7ca7f753fe10_terseLabel_en-US" xlink:label="lab_us-gaap_FairValueByAssetClassAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Fair Value by Asset Class [Axis]</link:label>
    <link:label id="lab_us-gaap_FairValueByAssetClassAxis_label_en-US" xlink:label="lab_us-gaap_FairValueByAssetClassAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Asset Class [Axis]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_FairValueByAssetClassAxis" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_FairValueByAssetClassAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FairValueByAssetClassAxis" xlink:to="lab_us-gaap_FairValueByAssetClassAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_dei_DocumentAnnualReport_4fdb2a82-c8d0-44ff-9203-bd8e6de65fb8_terseLabel_en-US" xlink:label="lab_dei_DocumentAnnualReport" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Document Annual Report</link:label>
    <link:label id="lab_dei_DocumentAnnualReport_label_en-US" xlink:label="lab_dei_DocumentAnnualReport" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Document Annual Report</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_dei_DocumentAnnualReport" xlink:href="https://xbrl.sec.gov/dei/2021q4/dei-2021q4.xsd#dei_DocumentAnnualReport"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_DocumentAnnualReport" xlink:to="lab_dei_DocumentAnnualReport" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_ScheduleofShareBasedCompensationSharesAvailableforIssuanceTable_3d856301-109f-4184-b3f4-2d42fca7ceab_terseLabel_en-US" xlink:label="lab_sigi_ScheduleofShareBasedCompensationSharesAvailableforIssuanceTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule of Share-Based Compensation Shares Available for Issuance [Table]</link:label>
    <link:label id="lab_sigi_ScheduleofShareBasedCompensationSharesAvailableforIssuanceTable_label_en-US" xlink:label="lab_sigi_ScheduleofShareBasedCompensationSharesAvailableforIssuanceTable" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule of Share-Based Compensation Shares Available for Issuance [Table]</link:label>
    <link:label id="lab_sigi_ScheduleofShareBasedCompensationSharesAvailableforIssuanceTable_documentation_en-US" xlink:label="lab_sigi_ScheduleofShareBasedCompensationSharesAvailableforIssuanceTable" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule of Share-Based Compensation Shares Available for Issuance [Table]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_ScheduleofShareBasedCompensationSharesAvailableforIssuanceTable" xlink:href="sigi-20211231.xsd#sigi_ScheduleofShareBasedCompensationSharesAvailableforIssuanceTable"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_ScheduleofShareBasedCompensationSharesAvailableforIssuanceTable" xlink:to="lab_sigi_ScheduleofShareBasedCompensationSharesAvailableforIssuanceTable" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_DividendRestrictionNewYork_e11bf8f5-bf0f-4c23-8289-a897df991ee2_terseLabel_en-US" xlink:label="lab_sigi_DividendRestrictionNewYork" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">New York Dividend Restriction on Adjusted Net Investment Income</link:label>
    <link:label id="lab_sigi_DividendRestrictionNewYork_label_en-US" xlink:label="lab_sigi_DividendRestrictionNewYork" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Dividend Restriction New York</link:label>
    <link:label id="lab_sigi_DividendRestrictionNewYork_documentation_en-US" xlink:label="lab_sigi_DividendRestrictionNewYork" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Percentage used in New York's dividend restriction calculation.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_DividendRestrictionNewYork" xlink:href="sigi-20211231.xsd#sigi_DividendRestrictionNewYork"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_DividendRestrictionNewYork" xlink:to="lab_sigi_DividendRestrictionNewYork" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_OtherComprehensiveIncomeLossTax_931201f9-af54-48a4-8ba1-07ca62ad5934_totalLabel_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeLossTax" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Other Comprehensive Income (Loss), Tax</link:label>
    <link:label id="lab_us-gaap_OtherComprehensiveIncomeLossTax_label_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeLossTax" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Other Comprehensive Income (Loss), Tax</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_OtherComprehensiveIncomeLossTax" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_OtherComprehensiveIncomeLossTax"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherComprehensiveIncomeLossTax" xlink:to="lab_us-gaap_OtherComprehensiveIncomeLossTax" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_DebtSecuritiesAvailableforsaleAllowanceforCreditLossNet_c36368cd-b319-47ea-af81-5f3e5b4ae936_terseLabel_en-US" xlink:label="lab_sigi_DebtSecuritiesAvailableforsaleAllowanceforCreditLossNet" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Credit loss expense, Net</link:label>
    <link:label id="lab_sigi_DebtSecuritiesAvailableforsaleAllowanceforCreditLossNet_label_en-US" xlink:label="lab_sigi_DebtSecuritiesAvailableforsaleAllowanceforCreditLossNet" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Debt Securities, Available-for-sale, Allowance for Credit Loss, Net</link:label>
    <link:label id="lab_sigi_DebtSecuritiesAvailableforsaleAllowanceforCreditLossNet_documentation_en-US" xlink:label="lab_sigi_DebtSecuritiesAvailableforsaleAllowanceforCreditLossNet" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Amount after tax of reclassification adjustment from accumulated other comprehensive income for unrealized amounts realized upon a credit-related impairment loss.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_DebtSecuritiesAvailableforsaleAllowanceforCreditLossNet" xlink:href="sigi-20211231.xsd#sigi_DebtSecuritiesAvailableforsaleAllowanceforCreditLossNet"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_DebtSecuritiesAvailableforsaleAllowanceforCreditLossNet" xlink:to="lab_sigi_DebtSecuritiesAvailableforsaleAllowanceforCreditLossNet" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_Assets_0e7b61d1-a9a8-4b71-96f1-dbbccbfbfdce_totalLabel_en-US" xlink:label="lab_us-gaap_Assets" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Total assets</link:label>
    <link:label id="lab_us-gaap_Assets_label_en-US" xlink:label="lab_us-gaap_Assets" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Assets</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_Assets" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_Assets"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_Assets" xlink:to="lab_us-gaap_Assets" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_PlanNameDomain_30a56dbe-3548-4451-9b10-618a23bbdc4f_terseLabel_en-US" xlink:label="lab_us-gaap_PlanNameDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Plan Name [Domain]</link:label>
    <link:label id="lab_us-gaap_PlanNameDomain_label_en-US" xlink:label="lab_us-gaap_PlanNameDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Plan Name [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_PlanNameDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_PlanNameDomain"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PlanNameDomain" xlink:to="lab_us-gaap_PlanNameDomain" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_FinanceLeaseLiabilityNotYetCommenced_8d8fbf3e-e3b7-4f06-8780-842a6dd60cc7_terseLabel_en-US" xlink:label="lab_sigi_FinanceLeaseLiabilityNotYetCommenced" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Finance Lease Liability Not Yet Commenced</link:label>
    <link:label id="lab_sigi_FinanceLeaseLiabilityNotYetCommenced_label_en-US" xlink:label="lab_sigi_FinanceLeaseLiabilityNotYetCommenced" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Finance Lease Liability Not Yet Commenced</link:label>
    <link:label id="lab_sigi_FinanceLeaseLiabilityNotYetCommenced_documentation_en-US" xlink:label="lab_sigi_FinanceLeaseLiabilityNotYetCommenced" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Amount of discounted liability of finance leases which have not yet commenced.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_FinanceLeaseLiabilityNotYetCommenced" xlink:href="sigi-20211231.xsd#sigi_FinanceLeaseLiabilityNotYetCommenced"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_FinanceLeaseLiabilityNotYetCommenced" xlink:to="lab_sigi_FinanceLeaseLiabilityNotYetCommenced" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_ScheduleofShareBasedCompensationRetiredPlansLineItems_38e75db1-2f40-4b5d-afa7-35fa7b4735cb_terseLabel_en-US" xlink:label="lab_sigi_ScheduleofShareBasedCompensationRetiredPlansLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule of Share-Based Compensation Retired Plans [Line Items]</link:label>
    <link:label id="lab_sigi_ScheduleofShareBasedCompensationRetiredPlansLineItems_label_en-US" xlink:label="lab_sigi_ScheduleofShareBasedCompensationRetiredPlansLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule of Share-Based Compensation Retired Plans [Line Items]</link:label>
    <link:label id="lab_sigi_ScheduleofShareBasedCompensationRetiredPlansLineItems_documentation_en-US" xlink:label="lab_sigi_ScheduleofShareBasedCompensationRetiredPlansLineItems" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">[Line Items] for Tabular disclosure of Schedule of Share-Based Compensation Retired Plans.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_ScheduleofShareBasedCompensationRetiredPlansLineItems" xlink:href="sigi-20211231.xsd#sigi_ScheduleofShareBasedCompensationRetiredPlansLineItems"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_ScheduleofShareBasedCompensationRetiredPlansLineItems" xlink:to="lab_sigi_ScheduleofShareBasedCompensationRetiredPlansLineItems" xlink:type="arc" order="1"/>
    <link:label id="lab_srt_ParentCompanyMember_8e2f8d27-6298-4a6d-9f88-10eb71e35952_terseLabel_en-US" xlink:label="lab_srt_ParentCompanyMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Parent Company [Member]</link:label>
    <link:label id="lab_srt_ParentCompanyMember_label_en-US" xlink:label="lab_srt_ParentCompanyMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Parent Company [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_srt_ParentCompanyMember" xlink:href="https://xbrl.fasb.org/srt/2021/elts/srt-2021-01-31.xsd#srt_ParentCompanyMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_srt_ParentCompanyMember" xlink:to="lab_srt_ParentCompanyMember" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_CommercialAutomobileMember_dbfd3421-dc3c-45c4-8a19-a0b392fd7c06_terseLabel_en-US" xlink:label="lab_sigi_CommercialAutomobileMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Commercial Automobile [Member]</link:label>
    <link:label id="lab_sigi_CommercialAutomobileMember_label_en-US" xlink:label="lab_sigi_CommercialAutomobileMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Commercial Automobile [Member]</link:label>
    <link:label id="lab_sigi_CommercialAutomobileMember_documentation_en-US" xlink:label="lab_sigi_CommercialAutomobileMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Represents insurance coverage provided to policy holders on commercial automobiles.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_CommercialAutomobileMember" xlink:href="sigi-20211231.xsd#sigi_CommercialAutomobileMember"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_CommercialAutomobileMember" xlink:to="lab_sigi_CommercialAutomobileMember" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_AllowanceForUncollectiblePremiumsReceivableTextBlock_2b8adc0a-1aad-43f1-8d22-2d0b11eabfa4_terseLabel_en-US" xlink:label="lab_sigi_AllowanceForUncollectiblePremiumsReceivableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Premium Receivable, Allowance for Credit Loss</link:label>
    <link:label id="lab_sigi_AllowanceForUncollectiblePremiumsReceivableTextBlock_label_en-US" xlink:label="lab_sigi_AllowanceForUncollectiblePremiumsReceivableTextBlock" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Allowance for Uncollectible Premiums Receivable [Text Block]</link:label>
    <link:label id="lab_sigi_AllowanceForUncollectiblePremiumsReceivableTextBlock_documentation_en-US" xlink:label="lab_sigi_AllowanceForUncollectiblePremiumsReceivableTextBlock" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">The entire disclosure for allowance for credit losses on Premiums Receivable.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_AllowanceForUncollectiblePremiumsReceivableTextBlock" xlink:href="sigi-20211231.xsd#sigi_AllowanceForUncollectiblePremiumsReceivableTextBlock"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_AllowanceForUncollectiblePremiumsReceivableTextBlock" xlink:to="lab_sigi_AllowanceForUncollectiblePremiumsReceivableTextBlock" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_NonRatedReinsurerAxis_33291666-7793-40d0-ac83-c7711492f46c_terseLabel_en-US" xlink:label="lab_sigi_NonRatedReinsurerAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Non Rated Reinsurer [Axis]</link:label>
    <link:label id="lab_sigi_NonRatedReinsurerAxis_label_en-US" xlink:label="lab_sigi_NonRatedReinsurerAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Non Rated Reinsurer [Axis]</link:label>
    <link:label id="lab_sigi_NonRatedReinsurerAxis_documentation_en-US" xlink:label="lab_sigi_NonRatedReinsurerAxis" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Reinsurers that are not rated by a rating agency.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_NonRatedReinsurerAxis" xlink:href="sigi-20211231.xsd#sigi_NonRatedReinsurerAxis"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_NonRatedReinsurerAxis" xlink:to="lab_sigi_NonRatedReinsurerAxis" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_DebtAndEquitySecuritiesRealizedGains_f21d8cb9-4798-4c1a-814d-be47659634e0_terseLabel_en-US" xlink:label="lab_sigi_DebtAndEquitySecuritiesRealizedGains" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Gross gains on sales</link:label>
    <link:label id="lab_sigi_DebtAndEquitySecuritiesRealizedGains_label_en-US" xlink:label="lab_sigi_DebtAndEquitySecuritiesRealizedGains" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Debt and Equity Securities, Realized Gains</link:label>
    <link:label id="lab_sigi_DebtAndEquitySecuritiesRealizedGains_documentation_en-US" xlink:label="lab_sigi_DebtAndEquitySecuritiesRealizedGains" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">This item represents the gross gain realized on sales of debt and equity investments.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_DebtAndEquitySecuritiesRealizedGains" xlink:href="sigi-20211231.xsd#sigi_DebtAndEquitySecuritiesRealizedGains"/>
    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_sigi_DebtAndEquitySecuritiesRealizedGains" xlink:to="lab_sigi_DebtAndEquitySecuritiesRealizedGains" xlink:type="arc" order="1"/>
    <link:label id="lab_us-gaap_ScheduleOfLineOfCreditFacilitiesTextBlock_b1c0b2ff-b560-406e-9af6-9f13b7c4d516_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfLineOfCreditFacilitiesTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Line of Credit Covenant Requirements</link:label>
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    <link:label id="lab_sigi_NetAssetValue_documentation_en-US" xlink:label="lab_sigi_NetAssetValue" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Net asset value of certain common stock investments that calculate net asset value per share.</link:label>
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    <link:label id="lab_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis_90e09b2b-c829-48ca-a548-d52619afa50a_terseLabel_en-US" xlink:label="lab_us-gaap_ShortdurationInsuranceContractsAccidentYearAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Short-duration Insurance Contracts, Accident Year [Axis]</link:label>
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    <link:label id="lab_us-gaap_SignificantAccountingPoliciesTextBlock_88c067d4-de16-45c4-8067-ad8be39f05de_terseLabel_en-US" xlink:label="lab_us-gaap_SignificantAccountingPoliciesTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Summary of Signifcant Accounting Policies</link:label>
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    <link:label id="lab_srt_CumulativeEffectPeriodOfAdoptionDomain_cae87a2b-52df-4df4-bbdb-d19d4e285e3f_terseLabel_en-US" xlink:label="lab_srt_CumulativeEffectPeriodOfAdoptionDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Cumulative Effect, Period of Adoption [Domain]</link:label>
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    <link:label id="lab_us-gaap_NetCashProvidedByUsedInOperatingActivities_19e63d86-cb42-42bc-96a6-0054bf40d4dd_totalLabel_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Net cash provided by operating activities</link:label>
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    <link:label id="lab_us-gaap_FurnitureAndFixturesMember_4807a314-6deb-4d5a-bbd5-b903a0b7536f_terseLabel_en-US" xlink:label="lab_us-gaap_FurnitureAndFixturesMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Furniture and fixtures [Member]</link:label>
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    <link:label id="lab_us-gaap_DebtInstrumentTable_985fc1ad-e6cd-4178-b40c-869e1c6403be_terseLabel_en-US" xlink:label="lab_us-gaap_DebtInstrumentTable" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule of Long-term Debt Instruments [Table]</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DebtInstrumentTable" xlink:to="lab_us-gaap_DebtInstrumentTable" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_TotalCommercialLinesMember_7f9faec1-2c6f-4955-befe-15bdc936c4f8_verboseLabel_en-US" xlink:label="lab_sigi_TotalCommercialLinesMember" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Total Standard Commercial Lines [Member]</link:label>
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    <link:label id="lab_sigi_TotalCommercialLinesMember_documentation_en-US" xlink:label="lab_sigi_TotalCommercialLinesMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Represents total commercial property and casualty coverage on the entity's commercial lines of business.</link:label>
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    <link:label id="lab_sigi_ProceedsFromEquityInvestmentsInExcessOfCurrentYearEarnings_8b4124c3-919a-45cb-9215-10af217910d1_terseLabel_en-US" xlink:label="lab_sigi_ProceedsFromEquityInvestmentsInExcessOfCurrentYearEarnings" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Distributions in excess of current year income of equity method investments</link:label>
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    <link:label id="lab_us-gaap_EarningsPerShareBasicAbstract_3b358334-7671-41af-9ebe-e6244bff7871_terseLabel_en-US" xlink:label="lab_us-gaap_EarningsPerShareBasicAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Basic EPS: [Abstract]</link:label>
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    <link:label id="lab_sigi_MunichReGroupMember_72e588cf-f0d0-4b9d-8709-be6250e0cf71_terseLabel_en-US" xlink:label="lab_sigi_MunichReGroupMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Munich Re Group [Member]</link:label>
    <link:label id="lab_sigi_MunichReGroupMember_label_en-US" xlink:label="lab_sigi_MunichReGroupMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Munich Re Group [Member]</link:label>
    <link:label id="lab_sigi_MunichReGroupMember_documentation_en-US" xlink:label="lab_sigi_MunichReGroupMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Represents Munich Re Group.</link:label>
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    <link:label id="lab_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_9dbab4f4-040e-4473-b2aa-5d0ccf715f58_terseLabel_en-US" xlink:label="lab_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Net income, basic shares</link:label>
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    <link:label id="lab_us-gaap_EarningsPerShareDiluted_4e3effc3-3d04-4510-8ba4-495f6004cf60_terseLabel_en-US" xlink:label="lab_us-gaap_EarningsPerShareDiluted" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Net income available to common stockholders - Diluted (in dollars per share)</link:label>
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    <link:label id="lab_us-gaap_EarningsPerShareDiluted_label_en-US" xlink:label="lab_us-gaap_EarningsPerShareDiluted" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Earnings Per Share, Diluted</link:label>
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    <link:label id="lab_us-gaap_SegmentDomain_7efdf05c-660f-455e-9f1b-b965034b07e4_terseLabel_en-US" xlink:label="lab_us-gaap_SegmentDomain" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Segment [Domain]</link:label>
    <link:label id="lab_us-gaap_SegmentDomain_label_en-US" xlink:label="lab_us-gaap_SegmentDomain" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Segments [Domain]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_SegmentDomain" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_SegmentDomain"/>
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    <link:label id="lab_us-gaap_ShortdurationInsuranceContractsAccidentYear2016Member_6b84da0e-8ca9-43ef-b0fc-dd39002aede3_terseLabel_en-US" xlink:label="lab_us-gaap_ShortdurationInsuranceContractsAccidentYear2016Member" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Short-duration Insurance Contracts, Accident Year 2016 [Member]</link:label>
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    <link:label id="lab_sigi_InvestmentsAccountedForUnderTheEquityMethodMember_documentation_en-US" xlink:label="lab_sigi_InvestmentsAccountedForUnderTheEquityMethodMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Represents investments accounted for under the equity method.</link:label>
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    <link:label id="lab_us-gaap_IncomeTaxesPaidNet_6cbae6f2-b786-46d4-814c-beed5565fd0c_terseLabel_en-US" xlink:label="lab_us-gaap_IncomeTaxesPaidNet" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Federal income tax</link:label>
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    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_IncomeTaxesPaidNet" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_IncomeTaxesPaidNet"/>
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    <link:label id="lab_sigi_UnrealizedGainLossOnInvestmentsAxis_808efc7d-27ce-425c-88f2-d9cd52fb6a37_terseLabel_en-US" xlink:label="lab_sigi_UnrealizedGainLossOnInvestmentsAxis" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Unrealized Gain Loss On Investments [Axis]</link:label>
    <link:label id="lab_sigi_UnrealizedGainLossOnInvestmentsAxis_label_en-US" xlink:label="lab_sigi_UnrealizedGainLossOnInvestmentsAxis" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Unrealized Gain Loss On Investments [Axis]</link:label>
    <link:label id="lab_sigi_UnrealizedGainLossOnInvestmentsAxis_documentation_en-US" xlink:label="lab_sigi_UnrealizedGainLossOnInvestmentsAxis" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">The disclosure of unrealized gains and losses on investments.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_UnrealizedGainLossOnInvestmentsAxis" xlink:href="sigi-20211231.xsd#sigi_UnrealizedGainLossOnInvestmentsAxis"/>
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    <link:label id="lab_sigi_ReturnonEquity_4e7d7978-ed23-440d-8e9e-91cdc9423421_terseLabel_en-US" xlink:label="lab_sigi_ReturnonEquity" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Return on Equity</link:label>
    <link:label id="lab_sigi_ReturnonEquity_label_en-US" xlink:label="lab_sigi_ReturnonEquity" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">ReturnonEquity</link:label>
    <link:label id="lab_sigi_ReturnonEquity_documentation_en-US" xlink:label="lab_sigi_ReturnonEquity" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">The after-tax income divided by average stockholders' equity.</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_sigi_ReturnonEquity" xlink:href="sigi-20211231.xsd#sigi_ReturnonEquity"/>
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    <link:label id="lab_us-gaap_ReinsuranceRecoverableCreditQualityIndicatorLineItems_5afd38ce-1ba4-4fcf-b02c-ebbeb2b6b0df_terseLabel_en-US" xlink:label="lab_us-gaap_ReinsuranceRecoverableCreditQualityIndicatorLineItems" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Reinsurance Recoverable, Credit Quality Indicator [Line Items]</link:label>
    <link:label id="lab_us-gaap_ReinsuranceRecoverableCreditQualityIndicatorLineItems_label_en-US" xlink:label="lab_us-gaap_ReinsuranceRecoverableCreditQualityIndicatorLineItems" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Reinsurance Recoverable, Credit Quality Indicator [Line Items]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_ReinsuranceRecoverableCreditQualityIndicatorLineItems" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_ReinsuranceRecoverableCreditQualityIndicatorLineItems"/>
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    <link:label id="lab_us-gaap_WorkersCompensationInsuranceMember_50e80a89-c246-4c74-9627-8e8d948073df_terseLabel_en-US" xlink:label="lab_us-gaap_WorkersCompensationInsuranceMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Workers Compensation [Member]</link:label>
    <link:label id="lab_us-gaap_WorkersCompensationInsuranceMember_label_en-US" xlink:label="lab_us-gaap_WorkersCompensationInsuranceMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Workers' Compensation Insurance [Member]</link:label>
    <link:loc xlink:type="locator" xlink:label="loc_us-gaap_WorkersCompensationInsuranceMember" xlink:href="https://xbrl.fasb.org/us-gaap/2021/elts/us-gaap-2021-01-31.xsd#us-gaap_WorkersCompensationInsuranceMember"/>
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    <link:label id="lab_us-gaap_DebtSecuritiesAvailableForSaleAllowanceForCreditLossTableTextBlock_7b3770a5-2a18-4dbe-a939-80acf5fe9ffb_terseLabel_en-US" xlink:label="lab_us-gaap_DebtSecuritiesAvailableForSaleAllowanceForCreditLossTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule of debt securities, available-for-sale, allowance for credit losses</link:label>
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    <link:label id="lab_us-gaap_ScheduleOfAmountsRecognizedInBalanceSheetTableTextBlock_53f87a05-cee6-4f07-b64a-da29a51ddec8_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfAmountsRecognizedInBalanceSheetTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule of Amounts Recognized in Consolidated Balance Sheet</link:label>
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    <link:label id="lab_sigi_LeaseAssetsandLiabilitiesTableTextBlock_f393017b-0141-458f-a266-136cc0390791_terseLabel_en-US" xlink:label="lab_sigi_LeaseAssetsandLiabilitiesTableTextBlock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Lease Assets and Liabilities</link:label>
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    <link:label id="lab_us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity_bd9318e1-9ad1-4e09-8962-2226a7da3ec8_terseLabel_en-US" xlink:label="lab_us-gaap_LineOfCreditFacilityCurrentBorrowingCapacity" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Line of credit borrowing capacity</link:label>
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    <link:label id="lab_sigi_TotalESLinesMember_92ed08c9-f19f-4880-aa09-54cafee2f399_terseLabel_en-US" xlink:label="lab_sigi_TotalESLinesMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Total E&amp;S Lines [Member]</link:label>
    <link:label id="lab_sigi_TotalESLinesMember_label_en-US" xlink:label="lab_sigi_TotalESLinesMember" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Total E&amp;S Lines [Member]</link:label>
    <link:label id="lab_sigi_TotalESLinesMember_documentation_en-US" xlink:label="lab_sigi_TotalESLinesMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Represents total E&amp;S property and casualty coverage on the entity's E&amp;S lines of business.</link:label>
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    <link:label id="lab_us-gaap_ProceedsFromSaleOfAvailableForSaleSecuritiesDebt_3bea67ed-bdef-472e-a66c-2b5937926518_terseLabel_en-US" xlink:label="lab_us-gaap_ProceedsFromSaleOfAvailableForSaleSecuritiesDebt" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Sale of fixed income securities, available-for-sale</link:label>
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    <link:label id="lab_us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossBeforeTax_06d67c9c-237a-4e2c-b8aa-39c14eca1666_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeLossReclassificationAdjustmentFromAOCIPensionAndOtherPostretirementBenefitPlansForNetGainLossBeforeTax" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Amount reclassified into net income: Net actuarial loss, Gross</link:label>
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    <link:label id="lab_us-gaap_DefinedBenefitPlanWeightedAverageAssumptionsUsedInCalculatingBenefitObligationAbstract_b1556ee0-5c49-4b1b-8c2c-4775f556c2c8_terseLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanWeightedAverageAssumptionsUsedInCalculatingBenefitObligationAbstract" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Weighted-Average Liability Asumptions</link:label>
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    <link:label id="lab_sigi_CommercialMortgageLoansSIGIMember_b4bf39f0-2d73-4f17-aa95-fd2de6095afd_terseLabel_en-US" xlink:label="lab_sigi_CommercialMortgageLoansSIGIMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Commercial Mortgage Loans SIGI</link:label>
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    <link:label id="lab_us-gaap_AllocatedShareBasedCompensationExpense_38dbe158-a8b7-4fe7-987d-1af79da5c43e_terseLabel_en-US" xlink:label="lab_us-gaap_AllocatedShareBasedCompensationExpense" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Share-based compensation expense, pre-tax</link:label>
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    <link:label id="lab_us-gaap_FinanceLeaseInterestPaymentOnLiability_18041af6-d495-4cfe-8dce-aa6d7e06d107_terseLabel_en-US" xlink:label="lab_us-gaap_FinanceLeaseInterestPaymentOnLiability" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Operating cash flows from financing leases</link:label>
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    <link:labelArc xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FinanceLeaseInterestPaymentOnLiability" xlink:to="lab_us-gaap_FinanceLeaseInterestPaymentOnLiability" xlink:type="arc" order="1"/>
    <link:label id="lab_sigi_LiabilityForAsbestosAndEnvironmentalClaimsNetIncurredLossSIGI_e3c6e676-7b8b-47b9-9871-41b64ff8b04d_terseLabel_en-US" xlink:label="lab_sigi_LiabilityForAsbestosAndEnvironmentalClaimsNetIncurredLossSIGI" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Incurred loss and loss expense, Net</link:label>
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    <link:label id="lab_us-gaap_SummaryOfInvestmentsOtherThanInvestmentsInRelatedPartiesFairValue_f69c1fda-71dd-40c1-ba83-c77ba746a274_terseLabel_en-US" xlink:label="lab_us-gaap_SummaryOfInvestmentsOtherThanInvestmentsInRelatedPartiesFairValue" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Fair Value</link:label>
    <link:label id="lab_us-gaap_SummaryOfInvestmentsOtherThanInvestmentsInRelatedPartiesFairValue_label_en-US" xlink:label="lab_us-gaap_SummaryOfInvestmentsOtherThanInvestmentsInRelatedPartiesFairValue" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">SEC Schedule, 12-15, Insurance Companies, Summary of Investments, Other than Investments in Related Parties, Fair Value</link:label>
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    <link:label id="lab_sigi_CashIncentivePlanMember_ba86ed59-8219-4646-b806-cf0f5aba9bfa_terseLabel_en-US" xlink:label="lab_sigi_CashIncentivePlanMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Cash Incentive Plan [Member]</link:label>
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    <link:label id="lab_sigi_CashIncentivePlanMember_documentation_en-US" xlink:label="lab_sigi_CashIncentivePlanMember" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">A liability share-based compensation arrangement.</link:label>
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    <link:label id="lab_sigi_ScheduleOfOtherInvestmentPortfolioByStrategyAndRemainingCommitmentAmountAssociatedWithEachStrategyTextblock_cd4d2024-99fd-49df-b444-608e4409799b_terseLabel_en-US" xlink:label="lab_sigi_ScheduleOfOtherInvestmentPortfolioByStrategyAndRemainingCommitmentAmountAssociatedWithEachStrategyTextblock" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Schedule of Other Investment Portfolio by Strategy and the Remaining Commitment Amount Associated With Each Strategy</link:label>
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    <link:label id="lab_us-gaap_AssetBackedSecuritiesMember_c97ed4b2-5b02-41aa-902a-92a98383c78a_terseLabel_en-US" xlink:label="lab_us-gaap_AssetBackedSecuritiesMember" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Collateralized Loan Obligations and Other Asset-Backed Securities [Member]</link:label>
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    <link:label id="lab_us-gaap_DefinedBenefitPlanAmountsRecognizedInBalanceSheet_96703cab-0892-4928-86e5-af0803727eef_totalLabel_en-US" xlink:label="lab_us-gaap_DefinedBenefitPlanAmountsRecognizedInBalanceSheet" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xmlns:xml="http://www.w3.org/XML/1998/namespace" xml:lang="en-US">Net pension asset (liability), end of year</link:label>
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