<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0206</schemaVersion>

    <documentType>3</documentType>

    <periodOfReport>2020-02-28</periodOfReport>

    <noSecuritiesOwned>0</noSecuritiesOwned>

    <issuer>
        <issuerCik>0001286613</issuerCik>
        <issuerName>LINCOLN EDUCATIONAL SERVICES CORP</issuerName>
        <issuerTradingSymbol>LINC</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001805376</rptOwnerCik>
            <rptOwnerName>Nyce Chad D</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O LINCOLN EDUCATIONAL SERVICES CORPORA</rptOwnerStreet1>
            <rptOwnerStreet2>200 EXECUTIVE DR., STE. 340</rptOwnerStreet2>
            <rptOwnerCity>WEST ORANGE</rptOwnerCity>
            <rptOwnerState>NJ</rptOwnerState>
            <rptOwnerZipCode>07052</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Chief Innovation Officer</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>120000</value>
                    <footnoteId id="F1"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">In connection with joining the Company as Chief Innovation Officer, the reporting person was granted 120,000 shares of restricted common stock under the Lincoln Educational Services Corporation's Amended and Restated 2005 Long-Term Incentive Plan, which shall vest 20% on March 15, 2021, 30% on March 15, 2022 and 50% on March 15, 2023, subject to the achievement of annual performance criteria. If an annual target is not met, the shares may vest cumulatively based on the achievement of cumulative economic targets.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Chad D Nyce</signatureName>
        <signatureDate>2020-03-04</signatureDate>
    </ownerSignature>
</ownershipDocument>
