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

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2017-02-22</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001095073</issuerCik>
        <issuerName>EVEREST RE GROUP LTD</issuerName>
        <issuerTradingSymbol>RE</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001463920</rptOwnerCik>
            <rptOwnerName>Addesso Dominic James</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>477 MARTINSVILLE ROAD</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>LIBERTY CORNER</rptOwnerCity>
            <rptOwnerState>NJ</rptOwnerState>
            <rptOwnerZipCode>07938</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>President and CEO</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Shares</value>
                <footnoteId id="F1"/>
                <footnoteId id="F2"/>
            </securityTitle>
            <transactionDate>
                <value>2017-02-22</value>
            </transactionDate>
            <deemedExecutionDate>
                <value>2017-02-22</value>
            </deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>10685</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>234.03</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>84119</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">The Common Shares are Restricted Common Shares awarded under the Company's 2010 Stock Incentive Plan.  The Restricted Shares will vest on February 22, 2018 (2,137 shares), February 22, 2019 (2,137 shares), February 22, 2020 (2,137 shares),  February 22, 2021 (2,137 shares) and  February 22, 2022 (2,137 shares)</footnote>
        <footnote id="F2">In addition, Mr. Addesso indirectly owns 1,000 Common Shares through the Addesso Family Trust.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/S/ SANJOY MUKHERJEE (Attorney-in-Fact)</signatureName>
        <signatureDate>2017-02-24</signatureDate>
    </ownerSignature>
</ownershipDocument>
