UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-A/A

(Amendment No. 5)

FOR REGISTRATION OF CERTAIN CLASSES OF SECURITIES

PURSUANT TO SECTION 12(b) OR (g) OF THE

SECURITIES EXCHANGE ACT OF 1934

Morgans Hotel Group Co.

(Exact name of registrant as specified in its charter)

Securities to be registered pursuant to Section 12(b) of the Act:

Securities Act registration statement file number to which this form relates:                             

(if applicable)

Securities to be registered pursuant to Section 12(g) of the Act:

None

(Title of Class)

Morgans Hotel Group Co. (the “Company”) hereby amends its Form 8-A dated October 10, 2007, as amended on July 30, 2008 and further amended on October 2, 2009, October 16, 2009 and April 22, 2010, relating to the Amended and Restated Stockholder Protection Rights Agreement (the “Rights Agreement”) between the Company and Computershare Shareowner Services LLC (f/k/a Mellon Investors Services LLC), as Rights Agent (“Computershare”), dated as of October 1, 2009 and as amended on October 15, 2009 and April 21, 2010. All capitalized terms used but not defined herein shall have the meaning ascribed to such term in the Rights Agreement.

On October 2, 2012, the Board of Directors of the Company resolved to amend the Rights Agreement. The Company and Computershare entered into Amendment No. 3 to the Rights Agreement, dated as of October 3, 2012 (“Amendment No. 3”), to amend the definition of “Expiration Time” to the earliest of (i) the Exchange Time, (ii) the Redemption Time, (iii) the Close of Business on October 9, 2015, unless, for purposes of this clause (iii), extended by action of the Board of Directors (in which case the applicable time shall be the time at which it has been so extended), and (iv) immediately prior to the effective time of a consolidation, merger or statutory share exchange that does not constitute a Flip-over Transaction or Event.

Amendment No. 3 is attached hereto as Exhibit 1, and is hereby incorporated herein by reference. The foregoing summary does not purport to be complete and is qualified in its entirety by reference to the full text of Amendment No. 3.

SIGNATURE

Pursuant to the requirements of Section 12 of the Securities Exchange Act of 1934, the registrant has duly caused this registration statement to be signed on its behalf by the undersigned, thereunto duly authorized.

Date: October 3, 2012

2

EXHIBIT INDEX