UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

SCHEDULE 14A

Proxy Statement Pursuant to Section 14(a) of the

Securities Exchange Act of 1934 (Amendment No.    )

Filed by the Registrant  x

Filed by a Party other than the Registrant  ¨

Check the appropriate box:

¨ Preliminary Proxy Statement

¨ Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2))

¨ Definitive Proxy Statement

x Definitive Additional Materials

¨ Soliciting Material Pursuant to §240.14a-12

    SandRidge Energy, Inc.    

(Name of Registrant as Specified In Its Charter)

(Name of Person(s) Filing Proxy Statement, if other than the Registrant)

Payment of Filing Fee (Check the appropriate box):

x No fee required.

¨ Fee computed on table below per Exchange Act Rules 14a-6(i)(1) and 0-11.

(1) Title of each class of securities to which the transaction applies:

(2) Aggregate number of securities to which the transaction applies:

(3) Per unit price or other underlying value of the transaction computed pursuant to Exchange Act Rule 0-11 (set forth the amount on which the filing fee is calculated and state how it was determined):

(4) Proposed maximum aggregate value of the transaction:

(5) Total fee paid:

¨ Fee paid previously with preliminary materials.

¨ Check box if any part of the fee is offset as provided by Exchange Act Rule 0-11(a)(2) and identify the filing for which the offsetting fee was paid previously. Identify the previous filing by registration statement number, or the Form or Schedule and the date of its filing.

(1) Amount Previously Paid:

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(4) Date Filed:

May 18, 2011

Dear Stockholder:

We have previously sent to you proxy material for the Annual Meeting of the stockholders of SandRidge Energy, Inc. to be held on June 3, 2011. Your Board of Directors has unanimously recommended that stockholders return the enclosed proxy card voting FOR Items 1, 2, 3, 4 and every 3 years for Item 5.

As you may know, due to recent changes to the NYSE rules, your broker is no longer entitled to vote your shares on certain of those proposals, including the election of Directors, without your instructions.

Your vote is important, no matter how many or how few shares you may own. Even if you have already done so, please vote TODAY by telephone, via the Internet, or by signing, dating and returning the enclosed proxy card in the envelope provided to ensure that your votes are validly received prior to the Annual Meeting.

Sincerely,

Philip T. Warman

Corporate Secretary

REMEMBER:

You can vote your shares by telephone, or via the Internet.

Please follow the easy instructions on the enclosed card.

If you have any questions, or need assistance in voting

your shares, please call our proxy solicitor,

INNISFREE M&A INCORPORATED

TOLL-FREE, at 1-888-750-5834.