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

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2012-09-11</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000109156</issuerCik>
        <issuerName>ZALE CORP</issuerName>
        <issuerTradingSymbol>ZLC</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001376259</rptOwnerCik>
            <rptOwnerName>Breeden Capital Management LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>100 NORTHFIELD STREET</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>GREENWICH</rptOwnerCity>
            <rptOwnerState>CT</rptOwnerState>
            <rptOwnerZipCode>06830</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001368419</rptOwnerCik>
            <rptOwnerName>Breeden Partners L.P.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>100 NORTHFIELD STREET</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>GREENWICH</rptOwnerCity>
            <rptOwnerState>CT</rptOwnerState>
            <rptOwnerZipCode>06830</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001370407</rptOwnerCik>
            <rptOwnerName>BREEDEN PARTNERS (CALIFORNIA) L.P.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>100 NORTHFIELD STREET</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>GREENWICH</rptOwnerCity>
            <rptOwnerState>CT</rptOwnerState>
            <rptOwnerZipCode>06830</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001433080</rptOwnerCik>
            <rptOwnerName>BREEDEN PARTNERS (CALIFORNIA) II LP</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>100 NORTHFIELD STREET</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>GREENWICH</rptOwnerCity>
            <rptOwnerState>CT</rptOwnerState>
            <rptOwnerZipCode>06830</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001448125</rptOwnerCik>
            <rptOwnerName>BREEDEN PARTNERS (NEW YORK) I L.P.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>100 NORTHFIELD STREET</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>GREENWICH</rptOwnerCity>
            <rptOwnerState>CT</rptOwnerState>
            <rptOwnerZipCode>06830</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001423997</rptOwnerCik>
            <rptOwnerName>Breeden Capital Partners LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>100 NORTHFIELD STREET</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>GREENWICH</rptOwnerCity>
            <rptOwnerState>CT</rptOwnerState>
            <rptOwnerZipCode>06830</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001300622</rptOwnerCik>
            <rptOwnerName>Breeden Richard C</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O BREEDEN CAPITAL MANAGEMENT LLC</rptOwnerStreet1>
            <rptOwnerStreet2>100 NORTHFIELD STREET</rptOwnerStreet2>
            <rptOwnerCity>GREENWICH</rptOwnerCity>
            <rptOwnerState>CT</rptOwnerState>
            <rptOwnerZipCode>06830</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2012-09-11</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>J</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>739521</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>4939550</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See footnote</value>
                    <footnoteId id="F2"/>
                    <footnoteId id="F3"/>
                    <footnoteId id="F5"/>
                    <footnoteId id="F4"/>
                    <footnoteId id="F6"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">On September 11, 2012, Breeden Partners (California) II L.P. (the &quot;California II Fund&quot;) distributed 743,657 shares of common stock of the Issuer (the &quot;Common Stock&quot;) to certain of its investors for no consideration, including 4,136 shares to Breeden Capital Partners LLC.</footnote>
        <footnote id="F2">The shares of Common Stock beneficially owned by the Reporting Owners directly following the distribution by the California II Fund of 743,657 shares of Common Stock are as follows: 33,686 shares by Breeden Partners L.P., 4,882,668 shares by Breeden Partners (California) L.P., and 23,196 shares by Breeden Capital Partners LLC (together with Breeden Partners L.P. and Breeden Partners (California) L.P., the &quot;Funds&quot;).</footnote>
        <footnote id="F3">The shares of Common Stock beneficially owned by the Reporting Owners indirectly following the distribution by the California II Fund of all of its 743,657 shares are as follows: 4,939,550 shares of Common Stock by Breeden Capital Partners LLC and 4,939,550 shares of Common Stock by Breeden Capital Management LLC; however, each such Reporting Owner disclaims beneficial ownership of such shares except to the extent of its pecuniary interest therein.</footnote>
        <footnote id="F4">Richard C. Breeden is the managing member of Breeden Capital Partners LLC and managing member and chairman and chief executive officer of Breeden Capital Management LLC, and, as such, may be deemed to be the indirect beneficial owner of the shares of Common Stock owned by Breeden Partners L.P., Breeden Partners (California) L.P., and the California II Fund; however, he disclaims beneficial ownership of such shares except to the extent of his pecuniary interest therein.  Richard Breeden is the holder of record of 10,942 shares.  Pursuant to the governing documents of the Funds, any economic interest realized with respect to these shares will be shared among the Funds and Breeden Capital Management LLC.</footnote>
        <footnote id="F5">Breeden Capital Management LLC is principally involved in the business of providing investment advisory and investment management services to Breeden Partners L.P., Breeden Partners (California) L.P. and the California II Fund  and, among other things, exercises all voting and other powers and privileges attributable to any securities held for the account of  such  funds and, as such, may be deemed to be the indirect beneficial owner of the shares of Common Stock owned by such funds; however, it disclaims beneficial ownership of such shares except to the extent of its pecuniary interest therein.</footnote>
        <footnote id="F6">Breeden Capital Partners LLC is the general partner of Breeden Partners L.P., Breeden Partners (California) L.P. and the California II Fund, and, as such, may be deemed to beneficially own the shares of Common Stock owned by such funds; however, it disclaims beneficial ownership of such shares except to the extent of its pecuniary interest therein.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Richard C. Breeden - See signatures included in Exhibit 99.1</signatureName>
        <signatureDate>2012-09-12</signatureDate>
    </ownerSignature>
</ownershipDocument>
