UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549





FORM 20-F/A

 ̈Registration statement pursuant to Section 12(b) or (g)

of the Securities Exchange Act of 1934

or

xAnnual report pursuant to Section 13 or 15(d)

of the Securities Exchange Act of
1934

FOR THE FISCAL YEAR ENDED NOVEMBER 30, 2013; or

 ̈Transition report pursuant to Section 13 or 15(d)

of the Securities Exchange Act of 1934

or

 ̈Shell company report pursuant to Section 13 or 15(d)

of the Securities Exchange
Act of 1934

Date of event requiring this shell company report:

For the transition period from  to

Commission file number: 1-35203







THERATECHNOLOGIES INC.

(Exact name of registrant as specified in its charter)

Quebec

(Jurisdiction of
incorporation or organization)

2310 Alfred-Nobel Blvd.

Montreal, Quebec, Canada, H4S 2B4

(Address of principal executive offices)

Luc Tanguay

Tel:
(514) 336-7800

Fax: (514) 331-9691

2310 Alfred-Nobel Boulevard

Montreal, Quebec, Canada H4S 2B4

(Name, Telephone, E-mail and/or Facsimile number and Address of Company Contact Person)





SECURITIES REGISTERED OR TO BE REGISTERED

PURSUANT TO SECTION 12(b) OF THE ACT:



|                                                  |  |                                                                       
|------------------------------------------------- |  | ----------------------------------------------------------------------
|Common Shares, no par value
(Title of each class) |  | The Toronto Stock Exchange
(Name of each exchange on which registered)





SECURITIES REGISTERED OR TO BE REGISTERED

PURSUANT TO SECTION 12(g) OF THE ACT:

N/A







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SECURITIES FOR WHICH THERE IS A REPORTING OBLIGATION

PURSUANT TO SECTION 15(d) OF THE ACT:

N/A





Indicate the number of
outstanding shares of each of the issuers classes of capital or common stock as of the close of the period covered by the annual report.

61,010,603
Common Shares

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

If this report is an annual or transition report,
indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934. Yes  ̈ No
x

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 requirements for the past
90 days. Yes x 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 (§232.405 of this chapter) during the preceding 12
months (or for such shorter period that the registrant was required to submit and post such files). Yes  ̈ No  ̈

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

 ̈ Large accelerated filer  ̈ Accelerated filer x Non-accelerated filer

Indicate by check mark which basis of accounting the registrant has used to prepare the
statements included in this filing:

U.S. GAAP  ̈ International Financial Reporting Standards as issued by
the International Accounting Standards Board x Other  ̈

If
Other has been checked in response to the previous question, indicate by check mark which financial statement item the registrant has elected to follow. Item 17  ̈ Item 18  ̈ |

If this is an annual report, indicate by check mark whether the registrant is a shell company (as defined in
Rule 12b-2 of the Exchange Act). Yes  ̈ No x





References in this Amendment
No. 1 to Form 20-F to Theratechnologies, the Company, the Corporation, we, our and us or similar terms refer to Theratechnologies Inc. and its subsidiaries on a
consolidated basis, unless otherwise indicated or unless the context requires otherwise.



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Explanatory Note

This Amendment No. 1 (this Amendment) to our annual report on Form 20-F for the fiscal year ended November 30, 2013, filed on
February 27, 2014 (the Form 20-F), is being filed solely to replace Exhibit 4.12 with the attached Exhibit 4.12 to reflect changes in the redacted portions of such exhibit in connection with our request for confidential treatment of
portions of such exhibit. These changes in redactions were made in response to comments that we received from the Securities and Exchange Commission regarding our confidential treatment request. Except as described above, no other change has been
made to the Form 20-F. The filing of this Amendment should not be understood to mean that any statements contained in the Form 20-F are true or complete as of any date subsequent to February 27, 2014.



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SIGNATURES

The registrant hereby certifies that it meets all of the requirements for filing on Form 20-F and that it has duly caused and authorized the
undersigned to sign this annual report on its behalf.



|                    |  |  |  |                        |  |                                      
|------------------- |  |  |  | ---------------------- |  | -------------------------------------
|                    |  |  |  | THERATECHNOLOGIES INC.
|                    |  |  | 
|Date: April 7, 2014 |  |  |  | By:                    |  | /s/ Luc Tanguay                      
|                    |  |  |  |                        |  | Name: Luc Tanguay                    
|                    |  |  |  |                        |  | President and Chief Executive Officer



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Exhibit Index

to Amendment No. 1 to Form 20-F



|              |  |                                                                                                                      
|------------- |  | ---------------------------------------------------------------------------------------------------------------------
|ExhibitNumber |  | Description of Exhibit                                                                                               
|              | 
|4.12          |  | Master Service Agreement dated December 10, 2013 between Ventiv Commercial Services, LLC and Theratechnologies Inc. +



|+ | Confidential treatment has been requested with respect to certain portions of this exhibit. Omitted portions have been filed separately with the SEC.
|- | -----------------------------------------------------------------------------------------------------------------------------------------------------



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