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

    <schemaVersion>X0304</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2011-11-28</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001494904</issuerCik>
        <issuerName>Global Indemnity plc</issuerName>
        <issuerTradingSymbol>GBLI</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001455952</rptOwnerCik>
            <rptOwnerName>Essex Equity Capital Management, LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>375 HUDSON STREET</rptOwnerStreet1>
            <rptOwnerStreet2>12TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10014</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>0001534789</rptOwnerCik>
            <rptOwnerName>Essex Equity Joint Investment Vehicle, LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>375 HUDSON STREET</rptOwnerStreet1>
            <rptOwnerStreet2>12TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10014</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>0001519005</rptOwnerCik>
            <rptOwnerName>Maher Basil</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O ESSEX EQUITY CAPITAL MANAGEMENT, LLC</rptOwnerStreet1>
            <rptOwnerStreet2>70 SOUTH ORANGE AVENUE, SUITE 105</rptOwnerStreet2>
            <rptOwnerCity>LIVINGSTON</rptOwnerCity>
            <rptOwnerState>NJ</rptOwnerState>
            <rptOwnerZipCode>07039</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>0001518965</rptOwnerCik>
            <rptOwnerName>Maher M. Brian</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O ESSEX EQUITY CAPITAL MANAGEMENT, LLC</rptOwnerStreet1>
            <rptOwnerStreet2>70 SOUTH ORANGE AVENUE, SUITE 105</rptOwnerStreet2>
            <rptOwnerCity>LIVINGSTON</rptOwnerCity>
            <rptOwnerState>NJ</rptOwnerState>
            <rptOwnerZipCode>07039</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>Class A Ordinary Shares</value>
            </securityTitle>
            <transactionDate>
                <value>2011-11-28</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>336</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>17.30</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1838503</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                    <footnoteId id="F1"/>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>Indirect</value>
                    <footnoteId id="F1"/>
                    <footnoteId id="F2"/>
                    <footnoteId id="F3"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">The amount of securities shown in this row is owned directly by Essex Equity Joint Investment Vehicle, LLC (the &quot;Fund&quot;).</footnote>
        <footnote id="F2">As the investment manager of the Fund, Essex Equity Capital Management, LLC (the &quot;Investment Manager&quot;) may be deemed to be a beneficial owner of the Issuer's securities held by the Fund.  The Investment Manager disclaims any beneficial ownership of any of the Issuer's securities reported herein for purposes of Section 16 of the Exchange Act, except to the extent of its pecuniary interest, if any.</footnote>
        <footnote id="F3">Each of Basil Maher and M. Brian Maher (collectively, the &quot;Individual Reporting Persons&quot;), as a member of the investment committee of the Investment Manager, may be deemed to be a beneficial owner of the Issuer's securities held by the Fund.  Each of the Individual Reporting Persons disclaims beneficial ownership of any of the Issuer's securities reported herein for purposes of Section 16 of the Exchange Act, except to the extent of his pecuniary interest, if any.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ John Liu, Chief Executive Officer of Essex Equity Capital Management, LLC</signatureName>
        <signatureDate>2011-11-30</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ John Liu, Chief Executive Officer of Essex Equity Capital Management, LLC, investment manager of Essex Equity Joint Investment Vehicle, LLC</signatureName>
        <signatureDate>2011-11-30</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Basil Maher</signatureName>
        <signatureDate>2011-11-30</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ M. Brian Maher</signatureName>
        <signatureDate>2011-11-30</signatureDate>
    </ownerSignature>
</ownershipDocument>
