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

    <schemaVersion>X0206</schemaVersion>

    <documentType>3</documentType>

    <periodOfReport>2015-11-18</periodOfReport>

    <noSecuritiesOwned>0</noSecuritiesOwned>

    <issuer>
        <issuerCik>0001512673</issuerCik>
        <issuerName>Square, Inc.</issuerName>
        <issuerTradingSymbol>SQ</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001471809</rptOwnerCik>
            <rptOwnerName>Khosla Ventures III, L.P.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>2128 SAND HILL ROAD</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>MENLO PARK</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94025</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001501934</rptOwnerCik>
            <rptOwnerName>Khosla Ventures Associates III, LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>2128 SAND HILL ROAD</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>MENLO PARK</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94025</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001501927</rptOwnerCik>
            <rptOwnerName>VK Services, LLC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>2128 SAND HILL ROAD</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>MENLO PARK</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94025</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001032453</rptOwnerCik>
            <rptOwnerName>KHOSLA VINOD</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>2128 SAND HILL ROAD</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>MENLO PARK</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94025</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <derivativeTable>
        <derivativeHolding>
            <securityTitle>
                <value>Series A Preferred Stock</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F3"/>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F3"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F3"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                    <footnoteId id="F1"/>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>41614640</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See footnote</value>
                    <footnoteId id="F2"/>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Series B-2 Preferred Stock</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F4"/>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F4"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F4"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                    <footnoteId id="F1"/>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>6321120</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See footnote</value>
                    <footnoteId id="F2"/>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Series C Preferred Stock</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F5"/>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F5"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F5"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                    <footnoteId id="F1"/>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>2587020</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See footnote</value>
                    <footnoteId id="F2"/>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeHolding>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Each share of Common Stock will be reclassified into one share of Class B Common Stock immediately prior to the completion of the Issuer's initial public offering of Class A Common Stock.</footnote>
        <footnote id="F2">Consists of securities held of record by Khosla Ventures III, L.P. (&quot;KV III&quot;), of which Khosla Ventures Associates III, LLC (&quot;KVA III&quot;) is the general partner. Vinod Khosla is the managing member of VK Services, LLC (&quot;VK Services&quot;), which is the manager of KVA III. Each of KVA III, VK Services and Vinod Khosla may be deemed to possess voting and investment control over such shares, and each of KVA III, VK Services and Vinod Khosla may be deemed to have indirect beneficial ownership of such shares. Each Reporting Person disclaims beneficial ownership of such shares except to the extent of his or its pecuniary interest therein.</footnote>
        <footnote id="F3">The Series A Preferred Stock is convertible into Common Stock on a 1:1 basis and has no expiration date. Immediately prior to the completion of the Issuer's initial public offering, all shares of Series A Preferred Stock will be converted into shares of Common Stock.</footnote>
        <footnote id="F4">The Series B-2 Preferred Stock is convertible into Common Stock on a 1:1 basis and has no expiration date. Immediately prior to the completion of the Issuer's initial public offering, all shares of Series B-2 Preferred Stock will be converted into shares of Common Stock.</footnote>
        <footnote id="F5">The Series C Preferred Stock is convertible into Common Stock on a 1:1 basis and has no expiration date. Immediately prior to the completion of the Issuer's initial public offering, all shares of Series C Preferred Stock will be converted into shares of Common Stock.</footnote>
    </footnotes>

    <remarks>Exhibit List
Exhibit 24 - Power of Attorney</remarks>

    <ownerSignature>
        <signatureName>/s/ Tamara L. Tompkins, as attorney in fact for Vinod Khosla, as Managing Member of VK Services, LLC, in its capacity as Manager of Khosla Ventures Associates III, LLC, in its capacity as general partner of Khosla Ventures III, L.P.</signatureName>
        <signatureDate>2015-11-18</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Tamara L. Tompkins, as attorney in fact for Vinod Khosla, as Managing Member of VK Services, LLC, in its capacity as Manager of Khosla Ventures Associates III, LLC</signatureName>
        <signatureDate>2015-11-18</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Tamara L. Tompkins, as attorney in fact for Vinod Khosla, as Managing Member of VK Services, LLC</signatureName>
        <signatureDate>2015-11-18</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Tamara L. Tompkins, as attorney in fact for Vinod Khosla</signatureName>
        <signatureDate>2015-11-18</signatureDate>
    </ownerSignature>
</ownershipDocument>
