SKADDEN, ARPS, SLATE, MEAGHER & FLOM

DIRECT DIAL 852-3740 4700 DIRECT FAX 852-3740 4727   PARTNERS JOHN ADEBIYI ¿ CHRISTOPHER W. BETTS EDWARD H.P. LAM ¿* G.S. PAUL MITCHARD QC ¿ CLIVE W. ROUGH ¿ JONATHAN B. STONE * ALEC P. TRACY * ¿ (ALSO ADMITTED IN ENGLAND & WALES) * (ALSO ADMITTED IN NEW YORK)   REGISTERED FOREIGN LAWYERS WILL H. CAI (CALIFORNIA) Z. JULIE GAO (CALIFORNIA) BRADLEY A. KLEIN (ILLINOIS) RORY MCALPINE (ENGLAND & WALES) GREGORY G.H. MIAO (NEW YORK) ALAN G. SCHIFFMAN (NEW YORK)     42/F, EDINBURGH TOWER, THE LANDMARK 15 QUEEN’S ROAD CENTRAL, HONG KONG                TEL: (852) 3740-4700 FAX: (852) 3740-4727 www.skadden.com       May 7, 2014 AFFILIATE OFFICES                BOSTON CHICAGO HOUSTON LOS ANGELES NEW YORK PALO ALTO WASHINGTON, D.C. WILMINGTON                BEIJING BRUSSELS FRANKFURT LONDON MOSCOW MUNICH PARIS SÃO PAULO SEOUL SHANGHAI SINGAPORE SYDNEY TOKYO TORONTO

VIA EDGAR

Barbara C. Jacobs, Assistant Director

Jan Woo, Attorney-Adviser

Christine Davis, Assistant Chief Accountant

Eiko Yaoita Pyles, Staff Accountant

Division of Corporation Finance

U.S. Securities and Exchange Commission

100 F Street, N.E.

Washington, DC 20549

Re: Cheetah Mobile Inc.

(formerly known as Kingsoft Internet Software Holdings Limited)

CIK No. 0001597835

Response to the Staff’s Oral Comments of May 6, 2014

Dear Ms. Jacobs, Ms. Woo, Ms. Davis and Ms. Pyles:

On behalf of our client, Cheetah Mobile Inc. (formerly known as Kingsoft Internet Software Holdings Limited), a foreign private issuer organized under the laws of the Cayman Islands (the “Company”), we submit to the staff (the “Staff”) of the Securities and Exchange Commission (the “Commission”) this letter setting forth the Company’s responses to the Staff’s oral comments of May 6, 2014. Capitalized terms used but not otherwise defined herein have the meanings set forth in the Company’s registration statement on Form F-1, as amended (the “Registration Statement”).

U.S. Securities and Exchange Commission

May 7, 2014

Page 2

1. Please explain the discrepancy between the MAU figures for Clean Master included in Annex 2-1 to the Company’s letter to the Staff dated March 26, 2014 and those in the Registration Statement on Form F-1 confidentially submitted on the same date.

The Company respectfully advises the Staff that Clean Master’s monthly active users (“MAU”) of 83.9 million as of December 31, 2013 cited in the F-1 confidentially submitted on March 26, 2014 were significantly higher than the 12.9 million contained in Annex 2-1 to the Company’s responses dated March 26, 2014 because the Company used its own internal record of the MAU instead of citing mUserTracker. mUserTracker only tracks MAU within China, but Clean Master has users in both China and overseas. In fact, Clean Master has a significantly larger overseas user base than in China. In addition, mUserTracker is a newly launched user data tracker that generates MAU based on limited samples of data within China. On the other hand, the Company believes that the ranking from mUserTracker still serves as a valuable reference for Clean Master’s ranking in China relative to competitive products in China. In the latest Form F-1/A filing, the MAU of Clean Master has been updated to 139.9 million as of March 31, 2014 and the Company’s internal record to support this data is attached as Annex I hereto.

In addition, the Company encloses, as Annex II hereto, the Company’s internal record for the MAU of Clean Master in December 2013. As indicated in the attached, the MAU of Clean Master in China was 29.7 million as of December 31, 2013. In comparison with the MAU provided by mUserTracker, i.e. 12.9 million, the Company’s MAU figure is higher. The reasons for the difference are set forth below:

• Prior to February 2014, iResearch had inadvertently allocated certain MAU of Clean Master to the Company’s other product called Kingsoft Mobile Guard. The Company was notified by iResearch by email of the error at the end of April 2014, and iResearch also issued a public notice about the errors in April 2014. The original mUserTracker MAU as of February 2014 was 16.8 million, and the amended MAU was 24.9 million. In other words, there was a rather significant difference of 8.1 million in February 2014. Please see Tables 2 and 3 in the attached excel file. mUserTracker had similarly underestimated the MAU of Clean Master as of December 31, 2013, which the Company estimates to be approximately 6 to 7 million.

• The research method used by mUserTracker does not keep pace with promotion channels of mobile applications in China, resulting in a tendency to underestimate MAU of mobile applications. iResearch applies samples according to gender, age, geographical area and network operator, and does not take into account the model of mobile phones.

U.S. Securities and Exchange Commission

May 7, 2014

Page 3

However, one of the Company’s principal methods of promoting Clean Master in China is by pre-installation on specific models of mobile phones. The inability to track pre-installation may have caused the mUserTracker data to significantly underestimate the MAU of those mobile phone models.

• The effective sample size of mobile devices tracked by mUserTracker is relatively small, which may lead to deviation from the actual MAU. mUserTracker currently uses 100,000 effective samples for mobile applications, in contrast with 400,000 effective samples for PC equipment. Larger sample size tends to increase the accuracy of research results, including MAU. Therefore, the mobile MAU from mUserTracker may not be as accurate as its PC MAU.

2. Please provide backup data for the updated March 2014 user data included in Amendment No. 3 to the Company’s Registration Statement on Form F-1 filed on May 5, 2014.

The Company encloses, as Annex III hereto, the backup data for the updated March 2014 user data included in Amendment No. 3 to the Company’s Registration Statement on Form F-1 filed with the Commission on May 5, 2014.

*        *        *

U.S. Securities and Exchange Commission

May 7, 2014

Page 4

If you have any questions regarding this letter or the Registration Statement, please contact the undersigned by phone at +852-3740-4863 or via e-mail at julie.gao@skadden.com or the audit engagement partner at Ernst & Young Hua Ming LLP, King Li, by telephone at +86-10-5815-2099, or by email at king.li@cn.ey.com. Ernst & Young Hua Ming LLP is the independent registered public accounting firm of the Company.

Very truly yours,

/s/ Z. Julie Gao

Z. Julie Gao

cc: Jun Lei, Chairman, Cheetah Mobile Inc.

Sheng Fu, Chief Executive Officer, Cheetah Mobile Inc.

Andy Yeung, Chief Financial Officer, Cheetah Mobile Inc.

King Li, Partner, Ernst & Young Hua Ming LLP

James C. Lin, Partner, Davis Polk & Wardwell LLP

Will H. Cai, Partner, Skadden, Arps, Slate, Meagher & Flom LLP

U.S. Securities and Exchange Commission

May 7, 2014

Page 7

Annex I

U.S. Securities and Exchange Commission

May 7, 2014

Page 6

Annex II

U.S. Securities and Exchange Commission

May 7, 2014

Page 7

Annex III

Tab	Statement in the F-1
P1	We had 362.0 million monthly active users for all of our applications in March 2014.
P1-2	It was also the No. 2 mobile utility application in China in terms of monthly active users in February 2014, according to iResearch, a third party market research firm.
P1-3	Duba Anti-virus, which is an internet security application, had 119.7 million monthly active users and 45.1 million average daily active users in March 2014.
P1-4	Cheetah Browser, which is our safe internet browser launched in June 2012 for PCs and June 2013 for mobile devices, had 44.1 million monthly active users and 14.9 million average daily active users in March 2014
P1-5	We are the second largest provider of internet security applications in China in terms of monthly active users in March 2014, according to iUser Tracker of iResearch.
P2	Duba.com personal start page, which aggregates popular online resources and provides users quick access to most of their online destinations, had 54.3 million monthly active users in March 2014, according to iResearch

P1

P1-2

P1-3

P1-4

P1-5

P2