UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

PURSUANT TO SECTION 13 OR 15(d) OF THE

SECURITIES EXCHANGE ACT OF 1934

Date of report (Date of earliest event reported): March 28, 2012

GENON ENERGY, INC.

(Exact name of registrant as specified in its charter)

Registrant’s telephone number, including area code: (832) 357-3000

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:

Item 7.01. Regulation FD Disclosure.

On March 28, 2012, Edward R. Muller, Chairman, President and Chief Executive Officer of GenOn Energy, Inc., will make a presentation at the 2012 Bank of America/Merrill Lynch Megawatt Round-up Conference. A copy of the presentation is furnished as exhibit 99.1 to this Form 8-K. This presentation is also available on the Investor Relations page of our website at www.genon.com.

Item 9.01. Financial Statements and Exhibits.

99.1—Presentation dated March 28, 2012

INFORMATION FURNISHED

The information in Item 7.01 and in the exhibit included as part of this Form 8-K are being furnished, not filed. Accordingly, the information will not be incorporated by reference into any filing or report by us with the Securities and Exchange Commission, whether made before or after the date hereof, unless specifically identified as being incorporated by reference therein.

CAUTIONARY STATEMENTS REGARDING FORWARD-LOOKING INFORMATION

This document contains statements, estimates or projections that constitute “forward-looking statements” as defined under U.S. federal securities laws. In some cases, one can identify forward-looking statements by words such as “will,” “expect,” “estimate,” “think,” “forecast,” “guidance,” “outlook,” “plan,” “lead,” “project” or comparable words. Forward-looking statements are subject to certain risks and uncertainties that could cause actual results to differ materially from our historical experience and our present expectations or projections. These risks include, but are not limited to: (i) legislative and regulatory initiatives or changes in regulations affecting the electric industry; (ii) changes in, or changes in the application of, environmental or other laws and regulations; (iii) failure of our generating facilities to perform as expected, including due to outages for unscheduled maintenance or repair; (iv) changes in market conditions or the entry of additional competition in our markets; and (v) those factors contained in our periodic reports filed with the Securities and Exchange Commission, including in the “Risk Factors” section of our most recent Annual Report on Form 10-K. The forward-looking information in this document is given as of the date of the particular statement, and we assume no duty to update this information. Our filings and other important information are also available on the Investor Relations page of our web site at www.genon.com.

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SIGNATURE

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.

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EXHIBIT INDEX