Sonia  Bjorkquist

Sonia Bjorkquist, Partner, Litigation

Contact Information

  • tel: 416.862.5876
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Bar Admission

Ontario, 1997


  • Queen’s University, LL.B.
  • University of Waterloo, B.A. (Hons.)






Sonia has expertise in the defence of complex litigation, large class actions and commercial arbitration, with extensive experience in trial advocacy and cross-border issues. She litigates business-critical issues related to director and officer liability, shareholder rights and oppression, corporate/commercial agreements and transactions, banking and ponzi schemes. Sonia defends complex product liability cases involving manufactured products, food and supplements, pharmaceuticals and medical devices, including defending allegations of negligent design and failure to warn. She also represents public and private sector organizations on access to information issues. Sonia is Chair of the firm’s Product Liability specialty group and Co-Chair of the firm’s International Commercial Arbitration specialty group.

Sonia is listed in Chambers Global: The World’s Leading Business Lawyers 2013 for Dispute Resolution, rated as AV Preeminent in Martindale-Hubbell’s Peer Review Ratings and named in Lexpert as a leading practitioner Consistently Recommended for class actions and Repeatedly Recommended for international commercial arbitration. Sonia is named as a leader in class actions in the 2013 Lexpert Guide to the Leading US/Canada Cross-Border Litigation Lawyers in Canada. She was selected by her peers in The Best Lawyers in Canada (8th ed.) for Product Liability Law. Sonia was recently elected as a member of the Federation of Defense and Corporate Counsel (FDCC), and is an active member of the Board of Directors of The Advocates’ Society. Prior to joining Osler as a lawyer, Sonia clerked for the Court of Appeal for Ontario.

Notable Matters

  • A leading pharmaceutical company in class actions and individual actions in several jurisdictions defending allegations of failure to warn.
  • A leading medical device company in class actions and individual actions in several jurisdictions defending product liability claims.
  • A major manufacturer of automotive parts in a long private arbitration involving a long-term supply agreement.
  • A leading international manufacturer of waste treatment equipment in defending complex product liability allegations.
  • A refinery in a long Ontario trial defending claims of alleged environmental contamination.
  • The Receivers of Stanford International Bank in proceedings regarding the forfeiture of funds related to an international fraud and ponzi scheme.
  • A major chartered bank in defending allegations of negligence and misrepresentation in individual and proposed class proceedings in three jurisdictions.
  • The directors and officers of a bankrupt company in a New Brunswick class action involving allegations of breach of fiduciary duty in respect of the administration of company pension plans.
  • A manufacturer of power transmission and distribution equipment in a long New Brunswick trial involving complex claims of breach of contract, negligence and failure to warn, including successfully defending an appeal taken to the Court of Appeal.
  • A technology company in a long Ontario trial involving claims by a former senior executive for lost stock options.
  • A leading financial processing services company in defence of claims by a former chief executive officer.
  • A private investment company in a long Ontario trial arising from a breached share purchase transaction, as well as successfully defending appeals taken to the Ontario Court of Appeal and Supreme Court of Canada.
  • Public sector organizations as respondents and affected third parties in Privacy Commission hearings.


  • The Advocates’ Society, Board of Directors, Chair of Education Committee, Chair of International Trip Committee
  • Federation of Defense and Corporate Counsel (FDCC), Elected Member
  • Defence Research Institute Member
  • Toronto Commercial Arbitration Society (TCAS), Member, Past Member of Executive Committee
  • Young Canadian Arbitration Practitioners (YCAP), Advisory Board, Past Member of Board of Directors and Past Vice-President
  • ADR Institute of Canada, Past Member of Board of Directors
  • Canadian Bar Association (Ontario) Member
  • American Bar Association Member, Litigation Section
  • International Bar Association Member
  • Toronto Lawyers Association Member

Industry Recognition

  • Martindale-Hubbell Peer Review Ratings: AV Preeminent
  • Chambers Global: The World’s Leading Business Lawyers 2014: Dispute Resolution – Ontario
  • The Canadian Legal Lexpert Directory 2014: Leading Practitioner Consistently Recommended for Class Actions; Repeatedly Recommended for International Commercial Arbitration; Litigation - Corporate Commercial
  • The 2013 Lexpert Guide to the Leading US/Canada Cross-Border Litigation Lawyers in Canada: Class Actions
  • The Best Lawyers in Canada 2015: Product Liability Law


  • The Oppression Remedy, Canada Law Book, loose leaf - updated annually since 2004 (co-authored with D. Morritt and A. Coleman).
  • Mastering Winning Discovery Techniques, Advocates’ Society, October 8, 2013 (co-chair).
  • Interviewed in The Law Times, "Are Class Actions Going to Trial More Often?" by Julius Melnitzer, September 2, 2013.
  • Class Actions in Canada 2012, Osler, Hoskin & Harcourt LLP, January 30, 2013 (co-authored).
  • Multi-Jurisdictional Classes: Does Van Breda Change Anything?, OBA Class Act, Vol. 3, No. 1, December 2012 (co-authored with M. Paterson).
  • Litigating a Cross-Border Class Action in Canada, ALM Cross-Border Litigation Forum, New York, September 12, 2012.
  • The New Emergency Arbitration Rules of the ICC, CBA National Section on International Law Newsletter, April 2012 (co-authored with E. Morgan).
  • Ethical Challenges in Arbitration Advocacy, Advocates’ Society Arbitration Advocacy, March 27, 2012 (Speaker).
  • Multi-jurisdictional Class Actions: Will the New CBA and ABA Protocols Solve all our Problems? Développements Récents en Recours Collectifs, Barreau du Québec, Vol. 345, March 2012 (co-authored with M. Eizenga and M. Paterson) (Speaker).
  • The Class Action Landscape for 2012: What In-House Counsel Needs to Know, Osler, Hoskin & Harcourt LLP, January 25, 2012 (Speaker).
  • Judicial Review or Damages? The Supreme Court of Canada’s Decision in Canada (A.G.) v. Telezone Inc., Annual Review of Civil Litigation 2011 (co-authored with J.M. Leclerc).
  • Leading Your Case: Opening Statements and Examination-in-Chief, Advocates’ Society, December 8, 2011 (co-chair).
  • What is Different About Advocacy in International Arbitration? Advocates’ Society, October 12, 2011 (co-chair).
  • Pre-Trial Tools: Winning Strategies and Checklists, Advocates’ Society Spring Symposium, May 12, 2011 (Speaker).
  • The New Ontario Rules: Same Book, Different Cover or Brave New World? Advocates’ Society Fall Convention, November 13, 2010 (Speaker).
  • Discovery Practice Under the New Rules, Advocates’ Society, November 4, 2010 (co-chair).
  • Costs Outcomes in Class Actions in Ontario: A Pragmatic Review of Costs Analysis in Recent Years, 2009 OBA Class Action Colloquium, December 1, 2009 (co-authored).
  • Litigating Shareholder Disputes, Osgoode Professional Development, June 2008 (co-chair and Speaker).
  • Defamation in the Internet Age, Osler Outlook, Fall 2008.

Pro Bono/Community Work

  • Osler Pro Bono Community Law, international human rights matters and Canadian civil liberties matter.