UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K/A

(Amendment No. 1)

CURRENT REPORT PURSUANT TO

SECTION 13 OR 15(d) OF THE

SECURITIES EXCHANGE ACT OF 1934

Date of report (Date of earliest event reported): April 5, 2013 (March 28, 2013)

MEMORIAL PRODUCTION PARTNERS LP

(Exact Name of Registrant as Specified in Charter)

Registrant’s telephone number, including area code: (713) 588-8300

Not Applicable

(Former Name or Former Address, if Changed Since Last Report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions:

EXPLANATORY NOTE

This Current Report on Form 8-K/A (“Amendment No. 1”) amends and supplements the Current Report on Form 8-K filed with the Securities and Exchange Commission by Memorial Production Partners LP (the “Partnership”) on March 28, 2013 (the “Form 8-K”) in connection with its March 28, 2013 acquisition of all of the outstanding equity interests in WHT Energy Partners LLC, which owns certain oil and natural gas producing and non-producing properties in East Texas and North Louisiana (the “WHT Acquisition”), for approximately $200 million, subject to customary post-closing adjustments. This Amendment No. 1 is filed to include audited financial statements and information required by Item 9.01(a) of Form 8-K and unaudited pro forma financial information as required by Item 9.01(b) of Form 8-K in connection with the WHT Acquisition as well as exhibits under Item 9.01(d) of Form 8-K. No other amendments to the Form 8-K are being made by this Amendment No. 1.

(a) Financial Statements of Businesses Acquired.

The audited balance sheets of WHT Energy Partners LLC as of December 31, 2012 and 2011 and the related statements of income, members’ equity, and cash flows for the year ended December 31, 2012 and period from February 2, 2011 (Inception) through December 31, 2011, including notes thereto, and the independent auditor’s report related thereto, are attached hereto as Exhibit 99.1 and incorporated herein by reference.

(b) Pro Forma Financial Information.

The unaudited pro forma condensed combined balance sheet of the Partnership as of December 31, 2012 and the unaudited condensed combined pro forma statements of operations for the year ended December 31, 2012, including notes thereto, which give effect to the WHT Acquisition and related financing transactions, are attached hereto as Exhibit 99.2 and incorporated herein by reference.

(d) Exhibits.

SIGNATURES

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

EXHIBIT INDEX