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

    <schemaVersion>X0206</schemaVersion>

    <documentType>3</documentType>

    <periodOfReport>2019-11-06</periodOfReport>

    <noSecuritiesOwned>0</noSecuritiesOwned>

    <issuer>
        <issuerCik>0001563577</issuerCik>
        <issuerName>Galera Therapeutics, Inc.</issuerName>
        <issuerTradingSymbol>GRTX</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001612133</rptOwnerCik>
            <rptOwnerName>Sofinnova Venture Partners IX, L.P.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O SOFINNOVA INVESTMENTS, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>3000 SAND HILL ROAD, BLDG. 4, SUITE 250</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>0001612134</rptOwnerCik>
            <rptOwnerName>Sofinnova Management IX, L.L.C.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O SOFINNOVA INVESTMENTS, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>3000 SAND HILL ROAD, BLDG. 4, SUITE 250</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>0001202793</rptOwnerCik>
            <rptOwnerName>POWELL MICHAEL</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O SOFINNOVA INVESTMENTS, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>3000 SAND HILL ROAD, BLDG. 4, SUITE 250</rptOwnerStreet2>
            <rptOwnerCity>MENLO PARK</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>94025</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001245624</rptOwnerCik>
            <rptOwnerName>HEALY JAMES</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O SOFINNOVA INVESTMENTS, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>3000 SAND HILL ROAD, BLDG. 4, SUITE 250</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>0001590102</rptOwnerCik>
            <rptOwnerName>Mehra Anand</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O SOFINNOVA INVESTMENTS, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>3000 SAND HILL ROAD, BLDG. 4, SUITE 250</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 B-2 Preferred Stock</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F2"/>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F2"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F2"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>1797843</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                    <footnoteId id="F1"/>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Series C Preferred Stock</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F2"/>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F2"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F2"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>535869</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                    <footnoteId id="F1"/>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">The shares reported herein are held of record by Sofinnova Venture Partners IX, L.P. (&quot;SVP IX&quot;). Dr. Michael F. Powell, Dr. James Healy and Dr. Anand Mehra are the managing members of Sofinnova Management IX, L.L.C., the general partner of SVP IX, and as such, may be deemed to share voting and investment power with respect to such shares.  Each of the reporting persons disclaims beneficial ownership of such securities, except to the extent of such person's pecuniary interest therein.</footnote>
        <footnote id="F2">Each share of the Issuer's preferred stock is convertible into shares of the Issuer's common stock on a 0.197763-for-one basis at the holder's election and has no expiration date. The preferred stock will automatically convert into common stock upon the closing of the Issuer's initial public offering.</footnote>
    </footnotes>

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

    <ownerSignature>
        <signatureName>/s/ Nathalie Auber, attorney-in-fact for Sofinnova Venture Partners IX, L.P.</signatureName>
        <signatureDate>2019-11-06</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Nathalie Auber, attorney-in-fact for Sofinnova Management IX, L.L.C.</signatureName>
        <signatureDate>2019-11-06</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Nathalie Auber, attorney-in-fact for Michael F. Powell</signatureName>
        <signatureDate>2019-11-06</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Nathalie Auber, attorney-in-fact for James Healy</signatureName>
        <signatureDate>2019-11-06</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ Nathalie Auber, attorney-in-fact for Anand Mehra</signatureName>
        <signatureDate>2019-11-06</signatureDate>
    </ownerSignature>
</ownershipDocument>
