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

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2015-04-10</periodOfReport>

    <notSubjectToSection16>1</notSubjectToSection16>

    <issuer>
        <issuerCik>0001588216</issuerCik>
        <issuerName>RSP Permian, Inc.</issuerName>
        <issuerTradingSymbol>RSPP</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001597326</rptOwnerCik>
            <rptOwnerName>Production Opportunities II, L.P.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>5221 N. O'CONNOR BLVD., SUITE 1100</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>IRVING</rptOwnerCity>
            <rptOwnerState>TX</rptOwnerState>
            <rptOwnerZipCode>75039</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>1</isOther>
            <otherText>Director by Deputization</otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001408123</rptOwnerCik>
            <rptOwnerName>Natural Gas Partners IX, L.P.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>5221 N. O'CONNOR BLVD., SUITE 1100</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>IRVING</rptOwnerCity>
            <rptOwnerState>TX</rptOwnerState>
            <rptOwnerZipCode>75039</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>1</isOther>
            <otherText>Director by Deputization</otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001592748</rptOwnerCik>
            <rptOwnerName>NGP IX Offshore Holdings, L.P.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>5221 N. O'CONNOR BLVD., SUITE 1100</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>IRVING</rptOwnerCity>
            <rptOwnerState>TX</rptOwnerState>
            <rptOwnerZipCode>75039</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>1</isOther>
            <otherText>Director by Deputization</otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001541519</rptOwnerCik>
            <rptOwnerName>G.F.W. ENERGY IX, L.P.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>5221 N. O'CONNOR BLVD., SUITE 1100</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>IRVING</rptOwnerCity>
            <rptOwnerState>TX</rptOwnerState>
            <rptOwnerZipCode>75039</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>1</isOther>
            <otherText>Director by Deputization</otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001597404</rptOwnerCik>
            <rptOwnerName>GFW IX, L.L.C.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>5221 N. O'CONNOR BLVD., SUITE 1100</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>IRVING</rptOwnerCity>
            <rptOwnerState>TX</rptOwnerState>
            <rptOwnerZipCode>75039</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>1</isOther>
            <otherText>Director by Deputization</otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001471812</rptOwnerCik>
            <rptOwnerName>NGP Energy Capital Management, L.L.C.</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>5221 N. O'CONNOR BLVD., SUITE 1100</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>IRVING</rptOwnerCity>
            <rptOwnerState>TX</rptOwnerState>
            <rptOwnerZipCode>75039</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>1</isOther>
            <otherText>Director by Deputization</otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2015-04-10</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>206077</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>25.65</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>4361950</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See Footnote</value>
                    <footnoteId id="F2"/>
                    <footnoteId id="F3"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2015-05-20</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F4"/>
                <footnoteId id="F5"/>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>4101261</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>28.00</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>260689</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See Footnote</value>
                    <footnoteId id="F2"/>
                    <footnoteId id="F3"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">On April 10, 2015, Production Opportunities II, L.P. (&quot;Production Opportunities&quot;) sold 206,077 shares of RSP Permian, Inc.'s (&quot;RSP&quot;) common stock, par value $0.01 per share (&quot;common stock&quot;), in connection with the exercise of the underwriter's option to purchase additional shares of common stock pursuant to the underwriting agreement, dated March 17, 2015, for a public offering of common stock by RSP, Production Opportunities and certain other stockholders of RSP.</footnote>
        <footnote id="F2">Held directly by Production Opportunities.</footnote>
        <footnote id="F3">This form is jointly filed by Production Opportunities, Natural Gas Partners IX, L.P. (&quot;NGP IX&quot;), NGP IX Offshore Holdings, L.P. (&quot;NGP Offshore&quot;), G.F.W. Energy IX, L.P. (&quot;GFW Energy&quot;), GFW IX, L.L.C. (&quot;GFW IX&quot;) and NGP Energy Capital Management, L.L.C. (&quot;NGP ECM&quot;).  GFW IX is the general partner of GFW Energy, which is the general partner of each of NGP IX and NGP Offshore, which jointly own Production Opportunities. GFW IX has delegated full power and authority to manage NGP IX and NGP Offshore to NGP ECM. Accordingly, each of NGP ECM, GFW IX, GFW Energy, NGP IX and NGP Offshore may be deemed to share voting and dispositive power over the reported securities and, as a result, may be deemed to beneficially own the reported securities. Each of NGP ECM, GFW IX, GFW Energy, NGP IX and NGP Offshore disclaim beneficial ownership of the reported securities in excess of their respective pecuniary interests therein.</footnote>
        <footnote id="F4">On May 20, 2015, Production Opportunities sold 4,101,261 shares of common stock pursuant to Rule 144 under the Securities Act of 1933, as amended.</footnote>
        <footnote id="F5">Following the sale, Production Opportunities no longer has the right pursuant to a Stockholders' Agreement to designate one nominee to the Board of Directors of RSP (the &quot;Board&quot;).  Also, as of RSP's annual meeting on May 20, 2015, David R. Albin, who was Production Opportunities' nominee to the Board, is no longer a member of the Board.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ James E. Mutrie, attorney-in-fact for Production Opportunities II, L.P.</signatureName>
        <signatureDate>2015-05-22</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ James E. Mutrie, attorney-in-fact for the general partner of the general partner of Natural Gas Partners IX, L.P.</signatureName>
        <signatureDate>2015-05-22</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ James E. Mutrie, attorney-in-fact for the general partner of the general partner of NGP IX Offshore Holdings, L.P.</signatureName>
        <signatureDate>2015-05-22</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ James E. Mutrie, attorney-in-fact for the general partner of G.F.W. Energy IX, L.P.</signatureName>
        <signatureDate>2015-05-22</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ James E. Mutrie, attorney-in-fact for GFW IX, L.L.C.</signatureName>
        <signatureDate>2015-05-22</signatureDate>
    </ownerSignature>

    <ownerSignature>
        <signatureName>/s/ James E. Mutrie, attorney-in-fact for NGP Energy Capital Management, L.L.C.</signatureName>
        <signatureDate>2015-05-22</signatureDate>
    </ownerSignature>
</ownershipDocument>
