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Peter Griffin K.C., LSM listen


Peter* is not a stranger to being in charge. In fact, he's known for it. Whatever side you are on, he is acclaimed for his tough but fair approach to his cases. Recognized as one of Canada's 25 Most Influential Lawyers, Peter commands§ respect from judges and opposing counsel for his fearless advocacy and extraordinary judgment. Peter tackles the most challenging commercial matters with expertise, because, after 35 years, he has the experience to skillfully guide his clients to success. Peter has a way of controlling the room from the boardroom up to the Supreme Court of Canada. He is a past President of The Advocates' Society and Fellow and former Chair of the American College of Trial Lawyers Ontario Committee. .



Peter Griffin , K.C., LSM

is counsel and one of the five founding partners at Lenczner Slaght.

"Peter Griffin is one of the best litigation lawyers in Canada. He has an excellent grasp of the issues and the law, as well as the gravitas to address difficult issues." — Chambers Canada

Peter is recognized by his peers as one of the top litigators in Canada, particularly in the areas of corporate commercial litigation, class actions, securities matters, insolvency, and professional and director/officer liability. He has appeared before all levels of court in Ontario and the common-law provinces, and before the Supreme Court of Canada. In 2021, Peter was recognized with the prestigious Law Society Medal for his exceptional advocacy, unwavering commitment to education and mentorship, and involvement in positively advancing the legal profession.

Peter has extensive experience in complex cross-border litigation, especially as it relates to both class proceedings and insolvency and restructuring. He regularly advises boards of directors and national and multinational corporations with respect to their obligations.  He is retained as counsel of choice on appeal. He frequently represents clients in arbitration and acts as an arbitrator in contested arbitration proceedings. Peter is constantly sought out as an expert speaker on advocacy, shareholder disputes, class actions, professional liability and insolvency and restructuring.

Peter is past President of The Advocates' Society, a Fellow of the American College of Trial Lawyers and past Chair of the American College of Trial Lawyers Ontario Committee.

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  • American College of Trial Lawyers - Fellow; Chair, Ontario Committee

  • The Advocates' Society - Past President 2012–2013

  • Canadian Bar Association

  • Ontario Bar Association

  • Sir William Campbell Foundation

  • Commercial List Users' Committee

  • Turnaround Management Association

  • Quadrennial Commission for Judicial Compensation - Commissioner (2016-2023)

  • Fixing the Mistake: Limitation Periods in Professional Negligence Cases

    Over a decade after Ontario’s Limitations Act, 2002 came into force, courts are still grappling with when a cause of action is discoverable and a limitation period starts to run.  An increasingly litigated question relates to whether a limitation period runs while efforts are ongoing to fix the error that gave rise to the plaintiff’s claim. The Court of Appeal for Ontario recently addressed this issue in Presidential MSH Corp v Marr, Foster & Co LLP.

    Peter Griffin | June 20, 2017

  • In contractual disputes, after-the-fact conduct is admissible after all

    To most people, a contract is a written agreement, typically signed by all parties, that sets out what different parties promise to do.  But what happens that the written agreement is ambiguous?  Courts have long held that evidence of the “factual matrix” of the contract—that is, the surrounding circumstances that inform the context in which a contract is created—is admissible in the interpretation of a contract.  In its recent decision in Shewchuk v Blackmont Capital Inc, the Ontario Court of Appeal confirmed that evidence of subsequent conduct may also be admissible to interpret the agreement itself.

    Peter Griffin & Paul-Erik Veel | December 8, 2016

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  • The Advocates' Society Medal (2024)

  • Law Society Medal (2021)

  • Ontario Bar Association Award for Excellence in Civil Litigation (2017)

  • American College of Trial Lawyers (2004)


  • Benchmark Canada (2012-2024)

    Top 50 Trial Lawyer in Canada & Litigation Star – Commercial, Competition, Insolvency, Professional Liability, Securities

  • Best Lawyers in Canada (2006-2024)

    Alternative Dispute Resolution, Appellate Practice, Bet-the-Company Litigation, Class Action Litigation, Corporate & Commercial Litigation, Director & Officer Liability, Health Care Law, Insolvency & Financial Restructuring, Legal Malpractice, Medical Negligence, Securities

  • Best Lawyers in Canada (2013)

    Toronto Corporate and Commercial Litigation "Lawyer of the Year"

  • Best Lawyers in Canada (2014)

    Toronto Bet-the-Company Litigation "Lawyer of the Year"

  • Best Lawyers in Canada (2016)

    Toronto "Lawyer of the Year" in Director and Officer Liability

  • Best Lawyers in Canada (2017)

    Toronto "Lawyer of the Year" in Corporate and Commercial Litigation

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