UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549



FORM 40-F/A

(Amendment No. 1)



| ̈ | REGISTRATION STATEMENT PURSUANT TO SECTION 12 OF THE SECURITIES EXCHANGE ACT OF 1934
|- | ------------------------------------------------------------------------------------



OR



|x | ANNUAL REPORT PURSUANT TO SECTION 13(a) OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934
|- | ---------------------------------------------------------------------------------------



For the fiscal year ended December 31,
2014



Commission file number: 001-34152



WESTPORT INNOVATIONS INC.

(Exact Name of Registrant as Specified in its
charter)



|Alberta                                                           | 3537                                                                      | N/A                                                    
|----------------------------------------------------------------- | ------------------------------------------------------------------------- | -------------------------------------------------------
|(Province or other jurisdiction of
incorporation or organization) | (Primary Standard Industrial 
Classification
Code Number (if applicable)) | (I.R.S. Employer Identification Number
(if applicable))



Suite 101, 1750 West 75th Avenue

Vancouver, British Columbia, Canada V6P 6G2

(604) 718-2000

(Address and telephone number of Registrant’s
principal executive offices)



|C T Corporation System                                   |  | Copies to:                  
|-------------------------------------------------------- |  | ----------------------------
|111 Eighth Avenue                                        |  | Gordon Caplan               
|New York, NY 10011                                       |  | Willkie Farr & Gallagher LLP
|(212) 590-9070                                           |  | 787 Seventh Avenue          
|(Name, address (including zip code) and telephone number |  | New York, New York 10019    
|(including                                               |  | (212) 728-8266              
|area code) of agent for service in the United States)    |  |                             



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



|Title of Each Class:        |  | Name of Each Exchange On Which Registered:
|--------------------------- |  | ------------------------------------------
|Common Shares, no par value |  | NASDAQ Global Select Market               



Securities registered or to be registered pursuant to Section 12(g) of
the Act:  N/A



Securities for which there is a reporting obligation pursuant to
Section 15(d) of the Act:  N/A

For annual reports, indicate by check mark the information filed
with this form:



| |  ̈ Annual Information Form |  | x Audited Annual Financial Statements
| | ------------------------- |  | -------------------------------------



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:  As at December 31, 2014,
63,480,722 common shares of the Registrant were issued and outstanding.



Indicate by check mark whether the Registrant (1) has filed
all reports required to be filed by Section 13 or 15(d) of the Exchange Act 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.         x   Yes                o  
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). x   Yes            ̈ 
No















EXPLANATORY NOTE



Westport Innovations Inc. (the “Company” or the
“Registrant”) is a Canadian issuer eligible to file its annual report pursuant to Section 13 of the Securities
Exchange Act of 1934, as amended (the “Exchange Act”), on Form 40-F pursuant to the multi-jurisdictional
disclosure system of the Exchange Act.  The Company is a “foreign private issuer” as defined in Rule 3b-4
under the Exchange Act.  Equity securities of the Company are accordingly exempt from Sections 14(a), 14(b), 14(c), 14(f) and
16 of the Exchange Act pursuant to Rule 3a12-3.



This Amendment No. 1 on Form 40-F (“Amendment No.
1”) amends the Company’s Annual Report on Form 40-F for the year ended December 31, 2014 filed with the
Securities and Exchange Commission on March 9, 2015 (the “Original Form 40-F”). The only amendments to the Original
Form 40-F are as follows: (i) Exhibit 99.2 (Audited consolidated financial statements of the Company and notes thereto for
the years ended December 31, 2014, 2013 and 2012 together with the Report of Independent Registered Public Accounting Firm thereon)
is being filed solely to include an amended Report of Independent Registered Public Accounting Firm with respect to the Company’s
internal control over financial reporting; and (ii) Exhibit 99.3 (Management’s Discussion and Analysis of Financial
Condition and Results of Operations for the year ended December 31, 2014) is being filed solely to include amended disclosure relating
to management’s identification of a material weakness in the Company’s internal control over financial reporting as
of December 31, 2014. This Amendment No. 1 does not amend the audited consolidated financial statements of the Company and the
notes thereto for the years ended December 31, 2014, 2013 and 2012.



Other than as discussed above, all information in the Original Form
40-F is unchanged and is not reproduced in this Amendment No. 1.  Except as may be specifically indicated herein, the Original
Form 40-F continues to describe conditions as of the date of the Original Form 40-F and the Company has not modified or updated
other disclosures presented in the Original Form 40-F.  This Amendment No. 1 does not reflect events occurring after
the date of the Original Form 40-F nor does it modify or update disclosures affected by subsequent events.  Accordingly, this
Amendment No. 1 should be read in conjunction with the Original Form 40-F.















UNDERTAKING



The Company undertakes to make available, in person or by telephone,
representatives to respond to inquiries made by the SEC’s staff, and to furnish promptly, when requested to do so by the
SEC staff, information relating to: the securities registered pursuant to Form 40-F; the securities in relation to which the obligation
to file an annual report on Form 40-F arises; or transactions in said securities.



CONSENT TO SERVICE OF PROCESS



The Company previously filed an Appointment of Agent for Service
of Process and Undertaking on Form F-X with the SEC on July 22, 2008, with respect to the class of securities in relation to which
the obligation to file this annual report on Form 40-F arises.











EXHIBIT INDEX



The following exhibits have been filed as part of this annual report:





|Exhibit            |  | Description                                                                                                                                                                                                                    
|------------------ |  | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
|                   |  |                                                                                                                                                                                                                                
|Annual Information
|99.1*              |  | Annual Information Form of the Company for the year ended December 31, 2014                                                                                                                                                    
|                   |  |                                                                                                                                                                                                                                
|99.2               |  | Audited consolidated financial statements of the Company and notes thereto for the years ended December 31, 2014, 2013 and 2012 together with the Reports of Independent Registered Public Accounting Firm thereon (as amended)
|                   |  |                                                                                                                                                                                                                                
|99.3               |  | Management’s Discussion and Analysis for the year ended December 31, 2014 (as amended)                                                                                                                                         
|                   |  |                                                                                                                                                                                                                                
|Certifications    
|99.4               |  | Certificate of Chief Executive Officer Pursuant to Section 302 of the Sarbanes-Oxley Act of 2002                                                                                                                               
|                   |  |                                                                                                                                                                                                                                
|99.5               |  | Certificate of Chief Financial Officer Pursuant to Section 302 of the Sarbanes-Oxley Act of 2002                                                                                                                               
|                   |  |                                                                                                                                                                                                                                
|99.6               |  | Certificate of Chief Executive Officer Pursuant to 18 U.S.C. Section 1350, as Adopted Pursuant to Section 906 of the Sarbanes-Oxley Act of 2002                                                                                
|                   |  |                                                                                                                                                                                                                                
|99.7               |  | Certificate of Chief Financial Officer Pursuant to 18 U.S.C. Section 1350, as Adopted Pursuant to Section 906 of the Sarbanes-Oxley Act of 2002                                                                                
|                   |  |                                                                                                                                                                                                                                
|Consents          
|99.8               |  | Consent of KPMG LLP                                                                                                                                                                                                            
|                   |  |                                                                                                                                                                                                                                
|99.9               |  | Consent of Deloitte LLP                                                                                                                                                                                                        
|                   |  |                                                                                                                                                                                                                                
|Exhibits          
|101.1*             |  | XBRL Interactive Data File                                                                                                                                                                                                     





*             
Previously filed with our Annual Report on Form 40-F on March 9, 2015











SIGNATURES



Pursuant to the requirements of the Exchange
Act, the Registrant certifies that it meets all of the requirements for filing on Form 40-F/A and has duly caused this annual report
to be signed on its behalf by the undersigned, thereto duly authorized.



| | WESTPORT INNOVATIONS INC.
| | -------------------------
| |                          
| | By:                      
| | Name:                    
| | Title:                   



Date: July 23, 2015