Terrence O'Sullivan LSM

Firm Co-Founder

Practice restricted to Dispute Resolution*

In Memoriam

It is with profound sadness that we advise that our wonderful friend and partner, Terry O'Sullivan, has passed away.

Terry is frequently retained and has acted as sole arbitrator, party nominee, chair, and appointed independent fact finder in arbitrations and mediations involving important commercial matters, often of an international nature. 

Terry had a broad commercial litigation practice, with particular expertise in business-related litigation including contract disputes, shareholder disputes, oppression remedies and securities litigation. He represented clients before all levels of Ontario Courts, the Federal Court, and the Supreme Court of Canada.

Terry is an active member of the legal profession, having published more than 70 papers on diverse litigation topics and acted as the long-time host for events such as the Canadian General Counsel Awards.  He is a Fellow of the American College of Trial Lawyers and the International Academy of Trial Lawyers.  Terry is a recipient of the Law Society of Ontario’s Medal for his outstanding contribution to the legal profession, and is a recipient of the Gold Key Award for Achievement from the Osgoode Hall Law School Alumni Association.  He is also a Past President of The Advocates' Society.

As one of the founding partners of the firm, Terry takes great pride in its ongoing culture of exceptional litigators who are collaborative, personable and directly available to their clients.

*Terry’s arbitration and mediation practice is conducted by him separately and independently of the firm.



  • The Canadian Academy of Distinguished Neutrals, Member
  • Harvard Law School Negotiation & Mediation Course
  • Chartered Institute of Arbitrators (MCIArb)
  • Called to the Ontario Bar, 1973
  • LL.B., Osgoode Hall Law School, 1971
  • B.A., University of Toronto, 1968
  • Sunnybrook Foundation, Director and Chair (and the 2011 Recipient of the Rose Award for Volunteer of the Year)
  • Women’s College Hospital, Past Director 
  • Toronto Rehab Hospital, Past Director

Terry is frequently referred to as a leading Canadian litigator by several rankings and publications, including Who’s Who Legal Canada, Chambers Canada, Benchmark Litigation Canada and Best Lawyers Canada as, inter alia, a Dean of the Canadian litigation bar, a leading litigator and a senior statesman of the litigation bar.

  • Benchmark Litigation Star, 2022: Commercial Litigation
  • The Best Lawyers™ in Canada, 2022: Alternative Dispute Resolution
  • Benchmark Litigation Star, 2021: Commercial Litigation
  • Canadian Lexpert® Directory, 2021: Litigation - Corporate Commercial; Class Actions; Litigation - Directors' & Officers' Liability; Litigation - Securities; Professional Liability
  • Lexpert®/ American Lawyer Guide - Leading 500 Lawyers in Canada, 2021: Litigation - Corporate Commercial
  • Legal 500 Canada, 2021: Leading Lawyer - Dispute Resolution, Ontario
  • The Best Lawyers™ in Canada, 2021: Administrative and Public Law; Alternative Dispute Resolution; Bet-the-Company Litigation; Class Action Litigation; Corporate and Commercial Litigation; Director and Officer Liability Practice; International Arbitration; Legal Malpractice Law; Securities Law
  • Canadian Lexpert® Directory, 2020: Litigation - Corporate Commercial; Litigation - Directors' & Officers' Liability; Litigation - Securities; Professional Liability
  • Benchmark Litigation Star, 2020
  • Chambers Canada 2020: Senior Statespeople - Litigation: General Commercial (Ontario)
  • The Best Lawyers™ in Canada, 2020:Bet-the-Company Litigation; Class Action Litigation; Corporate and Commercial Litigation; Director and Officer Liability Practice; Legal Malpractice Law; Securities Law
  • Legal 500, 2020 Edition: Leading Lawyer - Dispute Resolution, Ontario
  • Benchmark Litigation, 2019: Top 50 Trial Lawyer in Canada
  • Canadian Lexpert® Directory 2019: Litigation - Corporate Commercial, Professional Liability, Directors' & Officers' Liability, Litigation - Securities
  • Who's Who Legal, 2019: Thought Leader - Litigation, Global Litigation, Litigation - Canada
  • Benchmark Litigation, 2018: Top 50 Trial Lawyer in Canada 
  • Who's Who Legal, 2018: Thought Leader - Litigation; Global Litigation; Litigation - Canada