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

    <schemaVersion>X0206</schemaVersion>

    <documentType>3</documentType>

    <periodOfReport>2019-12-20</periodOfReport>

    <noSecuritiesOwned>0</noSecuritiesOwned>

    <issuer>
        <issuerCik>0001651052</issuerCik>
        <issuerName>Focus Financial Partners Inc.</issuerName>
        <issuerTradingSymbol>FOCS</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001796907</rptOwnerCik>
            <rptOwnerName>McGranahan John Russell</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>875 THIRD AVENUE, 28TH FLOOR</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10022</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>General Counsel</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Class A Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeHolding>
            <securityTitle>
                <value>Common Units in Focus Financial Partners, LLC</value>
            </securityTitle>
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            <exerciseDate>
                <footnoteId id="F1"/>
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            <expirationDate>
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            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Class A Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>14513</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Incentive Units in Focus Financial Partners, LLC</value>
            </securityTitle>
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                <footnoteId id="F4"/>
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                <underlyingSecurityTitle>
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                </underlyingSecurityTitle>
                <underlyingSecurityShares>
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                </underlyingSecurityShares>
            </underlyingSecurity>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Incentive Units in Focus Financial Partners, LLC</value>
            </securityTitle>
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                <footnoteId id="F4"/>
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                </underlyingSecurityTitle>
                <underlyingSecurityShares>
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            </underlyingSecurity>
            <ownershipNature>
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                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Incentive Units in Focus Financial Partners, LLC</value>
            </securityTitle>
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                <value>21.00</value>
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                <footnoteId id="F4"/>
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        <derivativeHolding>
            <securityTitle>
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                <footnoteId id="F4"/>
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            <expirationDate>
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            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
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        <derivativeHolding>
            <securityTitle>
                <value>Incentive Units in Focus Financial Partners, LLC</value>
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                <value>28.50</value>
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                <footnoteId id="F4"/>
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            <expirationDate>
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                <underlyingSecurityTitle>
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                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <footnoteId id="F2"/>
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            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
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        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Incentive Units in Focus Financial Partners, LLC</value>
            </securityTitle>
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                <footnoteId id="F7"/>
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            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Class A Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
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            </underlyingSecurity>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Incentive Units in Focus Financial Partners, LLC</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>22.00</value>
                <footnoteId id="F3"/>
                <footnoteId id="F4"/>
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            <exerciseDate>
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                <footnoteId id="F8"/>
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            <underlyingSecurity>
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                </underlyingSecurityTitle>
                <underlyingSecurityShares>
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                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Incentive Units in Focus Financial Partners, LLC</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>33.00</value>
                <footnoteId id="F3"/>
                <footnoteId id="F4"/>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F5"/>
                <footnoteId id="F9"/>
                <footnoteId id="F10"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F5"/>
                <footnoteId id="F9"/>
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            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Class A Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <footnoteId id="F5"/>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Incentive Units in Focus Financial Partners, LLC</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>28.50</value>
                <footnoteId id="F3"/>
                <footnoteId id="F4"/>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F5"/>
                <footnoteId id="F11"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F5"/>
                <footnoteId id="F11"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Class A Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <footnoteId id="F5"/>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
        <derivativeHolding>
            <securityTitle>
                <value>Incentive Units in Focus Financial Partners, LLC</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>27.90</value>
                <footnoteId id="F3"/>
                <footnoteId id="F4"/>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F5"/>
                <footnoteId id="F12"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F5"/>
                <footnoteId id="F12"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Class A Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <footnoteId id="F5"/>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Common units in Focus Financial Partners, LLC (&quot;Focus LLC&quot;) are exchangeable (together with an equal number of shares of Class B common stock of the Issuer), subject to certain restrictions in the Fourth Amended and Restated Operating Agreement of Focus LLC, for (i) an equal number of shares of the Issuer's Class A common stock or, (ii) at the election of the Issuer, cash.</footnote>
        <footnote id="F2">Vested incentive units are exchangeable, subject to certain restrictions in the Fourth Amended and Restated Operating Agreement of Focus LLC, for (i) a number of shares of the Issuer's Class A common stock that takes into account the then-current value of the Issuer's Class A common stock and such incentive units' aggregate hurdle amount or, (ii) at the election of the Issuer, cash.</footnote>
        <footnote id="F3">Each incentive unit in Focus LLC entitles the holder to receive distributions from Focus LLC if the aggregate distributions made by Focus LLC in respect of each common unit issued and outstanding on or prior to date of the grant of the incentive unit exceeds a specified amount, referred to as the hurdle amount. The hurdle amount is set at the time of grant and prior to the Issuer's initial public offering represented the estimated fair value of a common unit on the date of grant and since the Issuer's initial public offering is equal to the closing price on the date of grant of the Issuer's Class A common stock for which such incentive units may potentially be exchanged. The figure reflected in column 4 is the hurdle amount assigned to each incentive award. Incentive units do not expire.</footnote>
        <footnote id="F4">The Reporting Person beneficially owns 100,000 vested incentive units with a $16.00 hurdle amount, 75,213 vested incentive units with a $19.00 hurdle amount, 195,000 vested incentive units with a $21.00 hurdle amount, 67,880 vested incentive units with a $22.00 hurdle amount, 30,149 vested incentive units with a $28.50 hurdle amount, 125,000 unvested incentive units with a $21.00 hurdle amount, 67,879 unvested incentive units with a $22.00 hurdle amount, 500,000 unvested incentive units with a $33.00 hurdle amount, 90,448 unvested incentive units with a $28.50 hurdle amount, and 160,520 unvested incentive units with a $27.90 hurdle amount.</footnote>
        <footnote id="F5">Unvested incentive units will, at vesting, become exchangeable, subject to certain restrictions in the Fourth Amended and Restated Operating Agreement of Focus LLC, for (i) a number of shares of the Issuer's Class A common stock that takes into account the then-current value of the Issuer's Class A common stock and such incentive units' aggregate hurdle amount or, (ii) at the election of the Issuer, cash.</footnote>
        <footnote id="F6">These incentive units (the &quot;Retention Incentive Units) will be eligible to vest on the third anniversary of the Issuer's initial public offering if the weighted average price per share of the Issuer's Class A common stock for the ninety day period immediately preceding the third anniversary of the Issuer's initial public offering is: (i) less than $42.00, then no unvested Retention Incentive Units will vest; (ii) greater than $63.00, then all unvested Retention Incentive Units will vest; and (iii) if between $42.00 and $63.00, then (x) fifty percent (50%) of the unvested Retention Incentive Units will vest and (y) the remaining fifty percent (50%) of the unvested Retention Incentive Units will vest linearly based on where the price falls within the range of $42.00 and $63.00.</footnote>
        <footnote id="F7">If a change in control transaction occurs prior the third anniversary of the Issuer's initial public offering, any unvested Retention Units, subject to any superior provision in any employment agreement, will vest based on the price of the Issuer's Class A common stock used in the change in control transaction, applying the same vesting benchmarks as are applied on the third anniversary of the Issuer's initial public offering.</footnote>
        <footnote id="F8">These incentive units will vest in two equal installments on November 22, 2020 and November 22, 2021.</footnote>
        <footnote id="F9">These incentive units will vest on the fifth anniversary of the pricing of the Issuer's initial public offering provided that the volume weighted average price per share of the Issuer's Class A common stock for any ninety calendar day period within such five year period reaches at least $100.00.</footnote>
        <footnote id="F10">In the event a change in control transaction occurs prior to the end of such five year period, the incentive units, subject to any superior provision in any employment agreement, will vest linearly based on where the price of the Issuer's Class A common stock used in the transaction falls between the stock price in connection with the Issuer's initial public offering and $100.00, with 100% vesting if the price of the Issuer's Class A common stock used in the transaction is at least $100.00, 0% vesting if the price of the Issuer's Class A common stock used in the transaction is equal to or less than the price of the Issuer's Class A common stock in the Issuer's initial public offering, and linear interpolation in between.</footnote>
        <footnote id="F11">These incentive units will vest in three equal installments on December 18, 2020, December 18, 2021 and December 18, 2022.</footnote>
        <footnote id="F12">These incentive units will vest in four equal installments on December 11, 2021, December 11, 2022, December 11, 2023 and December 11, 2024.</footnote>
    </footnotes>

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

    <ownerSignature>
        <signatureName>/s/ J. Russell McGranahan</signatureName>
        <signatureDate>2019-12-20</signatureDate>
    </ownerSignature>
</ownershipDocument>
