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UNITED STATES SECURITIES AND
EXCHANGE COMMISSION

Washington, D.C. 20549

Form 10-K/A

Amendment No. 1



|           |  |                                                                                         
|---------- |  | ----------------------------------------------------------------------------------------
|(Mark One) |  |                                                                                         
|þ          |  | ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934    
|           |  | For the fiscal year ended December 31, 2011
 or                                         
| ̈          |  | TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934
|           |  | For the transition period from                  to                                      

Commission File Number 000-21433

Forrester Research, Inc.

(Exact name of registrant as specified in its charter)



|                                                              |  |                                       
|------------------------------------------------------------- |  | --------------------------------------
|Delaware                                                      |  | 04-2797789                            
|(State or other jurisdictionof incorporation or organization) |  | (I.R.S. EmployerIdentification Number)
|60 Acorn Park Drive                                           |  | 02140                                 
|Cambridge, Massachusetts                                      |  | (Zip Code)                            
|(Address of principal executive offices)                      |  |                                       

Registrants telephone number, including area code:

(617) 613-6000

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



|                             |  |                                          
|---------------------------- |  | -----------------------------------------
|Title of Each Class          |  | Name of Each Exchange on Which Registered
|Common Stock, $.01 Par Value |  | Nasdaq Global Select Market              

Securities to be registered pursuant to Section 12(g) of the Act: None

Indicate by check mark if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities
Act.     Yes   ̈    No  þ

Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the
Act.     Yes    ̈    No   þ

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the
Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirement for the past
90 days.    Yes  þ    No   ̈

Indicate by check mark whether the registrant has submitted electronically and posted on its corporate Web site, if any, every Interactive
Data File required to be submitted and posted pursuant to Rule 405 of Regulation S-T during the preceding 12 months (or for such shorter period that the registrant was required to submit and post such files.)
    Yes  þ    No   ̈

Indicate by check mark if disclosure of delinquent filers pursuant to Item 405 of Regulation S-K (§ 229.405 of this chapter) is not contained herein, and will not be contained, to the
best of registrants knowledge, in definitive proxy or information statements incorporated by reference in Part III of this Form 10-K or any amendment to this Form 10-K.  ̈

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, or
a smaller reporting company. See the definitions of large accelerated filer, accelerated filer and smaller reporting company in Rule 12b-2 of the Exchange Act. (Check one):

|                          |  |                                               |  |                         |  |                            
|------------------------- |  | --------------------------------------------- |  | ----------------------- |  | ---------------------------
|Large accelerated filer  ̈ |  | Accelerated filer þ                           |  | Non-accelerated filer  ̈ |  | Smaller reporting company  ̈
|                          |  | (Do not check if a smaller reporting company)

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the
Act).     Yes   ̈    No  þ

The aggregate market value of the registrants common stock held by non-affiliates of the registrant as of June 30, 2011 (based
on the closing price as quoted by the Nasdaq National Market as of such date) was approximately $486,000,000.

As of
March 6, 2012, 22,714,000 shares of the registrants common stock were outstanding.

DOCUMENTS INCORPORATED BY
REFERENCE

Portions of the registrants Proxy Statement related to its 2012 Annual Stockholders Meeting to be
filed subsequently  Part III of this Form 10-K.









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TABLE OF CONTENTS



|                                                    |  |      |   | 
|--------------------------------------------------- |  | ---- | - | 
|                                                    |  | PAGE |  
|                                                    | 
|EXPLANATORY NOTE                                    |  |      | 1 | 
|                                                    | 
|ITEM                                                |  |      |   | 
|                                                    | 
|PART IV                                             |  |      | 2 | 
|                                                    | 
|Item 15. Exhibits and Financial Statement Schedules |  |      | 2 | 
|                                                    | 
|Signatures                                          |  |      | 3 | 
|                                                    | 
|Exhibit Index                                       |  |      | 4 | 



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EXPLANATORY NOTE

Forrester Research, Inc. is filing this Amendment No. 1 (Amendment) on Form 10-K/A to amend its Annual Report on Form 10-K for the year
ended December 31, 2011 to correct an incomplete Exhibit 23.1 filed with the original report. Exhibit 23.1 of the original filing did not include the date of the report of PricewaterhouseCoopers LLP relating to our consolidated financial
statements and the effectiveness of our internal control over financial reporting. The corrected Exhibit 23.1 filed herewith includes the date of such report, March 9, 2012.

There are no changes to the Original Form 10-K other than those set forth above. This Amendment does not reflect events occurring after the filing of the Original Form 10-K, nor does it modify or update
disclosures therein in any way. Among other things, forward-looking statements made in the Original Form 10-K have not been revised to reflect events that occurred or facts that became known to us after the filing of the Original Form 10-K, and such
forward-looking statements should be read in their historical context. Furthermore, the Amendment should be read in conjunction with the Original Form 10-K and with our filings with the SEC subsequent to the Original Form 10-K.



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PART IV



|Item 15. | Exhibits and Financial Statement Schedules.
|-------- | -------------------------------------------

c. Exhibits.    A listing of exhibits required is given in the Exhibit Index that precedes the exhibits filed with this report on page 4 hereof.



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SIGNATURES

Pursuant to the requirements of Section 13 or 15(d) of the Securities Exchange Act of 1934, the registrant has duly caused this
report to be signed on its behalf by the undersigned, thereunto duly authorized.



| |  |  |  |                          |  |                                      
| |  |  |  | ------------------------ |  | -------------------------------------
| |  |  |  | FORRESTER RESEARCH, INC.
| |  |  | 
| |  |  |  | By:                      |  | /s/    MICHAEL A. DOYLE              
| |  |  |  |                          |  | Michael A. Doyle                     
| |  |  |  |                          |  | Chief Financial Officer and Treasurer

Date: March 12, 2012



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EXHIBIT INDEX

Exhibit 23.1        Consent of PricewaterhouseCoopers LLP

Exhibit 31.1        Certification of the Chief Executive Officer

Exhibit 31.2        Certification of the Chief Financial Officer



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