July 8, 2013

Via: EDGAR and Facsimile

Securities and Exchange Commission
Division of Corporation Finance
100 F Street, NE
Washington, DC 20549
Attention: Amanda Ravitz

Ladies and Gentlemen:

Pursuant to Rule 461 promulgated under the Securities Act of 1933, as amended, Security Devices International Inc., respectfully requests that the Commission accelerate the effectiveness of the above-referenced Amendment No. 3 to the Registration Statement on Form S-1/A (File No. 333-187138), and permit said amended Registration Statement to become effective at 10:00 a.m. (Eastern Time) on July 11, 2013, or as soon thereafter as practicable.

Security Devices International Inc., hereby authorizes Richard Raymer, an attorney with our outside legal counsel, Dorsey & Whitney LLP, to orally modify or withdraw this request for acceleration.

Security Devices International Inc. hereby acknowledges that:

• should the Commission or the staff, acting pursuant to delegated authority, declare the filing effective, it does not foreclose the Commission from taking any action with respect to the filing;

• the action of the Commission or the staff, acting pursuant to delegated authority, in declaring the filing effective, does not relieve the company from its full responsibility for the adequacy and accuracy of the disclosure in the filing; and

• the company may not assert staff comments and the declaration of effectiveness as a defense in any proceeding initiated by the Commission or any person under the federal securities laws of the United States.

Please contact the undersigned at (202) 756-1960 or Richard Raymer of Dorsey & Whitney LLP at (416) 367-7388 with any questions with respect to this request.

Very truly yours,

Security Devices International Inc.

By: /s/ Gregory Sullivan                       
       Name: Gregory Sullivan 
       Title: Chief Executive Officer

cc: Richard Raymer, Dorsey & Whitney LLP