Guy Pratte

Guy J. Pratte

Senior Counsel

613.787.3521  416.350.2638  514.954.2545

An award-winning and highly sought-after lawyer, Guy has experience in complex commercial litigation (including class actions), administrative law and constitutional law cases.

Guy frequently appears before the Supreme Court of Canada (SCC), the Superior and Appeal Courts of Ontario and Québec, the Federal Court (FC) and Federal Court of Appeal (FCA).


  • Trinity Western University v. Law Society of Upper Canada (under reserve), November/December 2017)
  • Deloitte & Touche v. Livent Inc., 2017 SCC 36875
  • World Bank Group v. Wallace, 2016 SCC 15
  • Canadian National Railway Co. v. Canada (Attorney General), 2014 SCC 40
  • Hinse v. Canada (Attorney General), 2013 S.C.C.A. 448
  • Québec (Attorney General) v. A., 2013 SCC 5
  • Cinar Corporation v. Robinson, 2013 SCC 73
  • S.L. v. Commission scolaire des Chênes, 2012 SCC 7
  • Canada (Attorney General) v. PHS Community Services Society, 2011 SCC 44
  • Bou Malhab v. Diffusion Métromédia CMR Inc., 2011 SCC 9
  • Ontario (Public Safety and Security) v. Criminal Lawyers’ Association, 2010 SCC 23
  • Canadian National Railway Co. v. Royal and Sun Alliance Insurance Co. of Canada, 2008 SCC 66
  • Chaoulli v. Québec (Attorney General), 2005 SCC 35
  • Finney v. Barreau du Québec, 2004 SCC 36
  • Lead counsel for Canadian National Railway Co. in an appeal against Richardson International Ltd. before the FCA
  • Lead counsel for the Board of Internal Economy and The Honourable Andrew Scheer (speaker of the House of Commons) in several judicial review applications commenced by the NDP in the FC
  • Lead counsel for the Law Society of Upper Canada in a judicial review application commenced by Trinity Western University in the Ontario Divisional Court
  • Commissioner of Official Languages of Canada v. CBC/Radio-Canada, 2014 FC 849
  • McCracken v. Canadian National Railway Co., 2012 ONCA (Ontario Court of Appeal) 445 (class certification reversed on appeal)
  • Pelletier v. Canada (Attorney General), 2008 FC 803
  • Independent counsel for the Canadian Judicial Council in the matter of certain allegations made against ACJ Douglas of the Manitoba Court of Queen’s Bench, 2011-2012
  • Lead counsel for the Right Honourable Brian Mulroney before the Oliphant Commission of Inquiry, 2008-2010
  • Lead counsel for Mr. Jean Pelletier (former chief of staff to the Right Honourable Prime Minister of Canada Jean Chrétien) before the Commission of Inquiry into the Sponsorship Program and Advertising Activities before the Federal Court and Federal Court of Appeal
  • Lead counsel for JTI-MacDonald and RJR Tobacco Companies in ongoing healthcare cost recovery actions brought by the Governments of Ontario (C$50B) and Québec (C$60B)
  • Lead counsel for JTI MacDonald in ongoing tobacco-related class actions in the province of Québec (C$20B)

Beyond Our Walls

Professional Involvement

  • Chair, Pro Bono Ontario
  • Fellow, American College of Trial Lawyers (2007-present)
  • President, The Advocates' Society (2020-2021)
  • Co-chair, Access to Justice Committee, American College of Trial Lawyers (2010- 2013)
  • Director and Vice-Chair, Supreme Court Advocacy Institute (2009)
  • Director and Officer, Canadian Institute for Advanced Legal Studies (2008-present)
  • Adjunct professor, “The Supreme Court of Canada in Search of Justice,” University of Toronto Law School
  • Former Milvain Chair in Advocacy, University of Calgary Law School
  • Former adjunct professor, University of Ottawa common law program
  • Former adjunct professor, “A Virtual Tour of the Modern Practice of Law,” University of Western Ontario
  • Former adjunct Professor, “Common Law Contracts,” Université de Montréal
  • Founder and former president, Pro Bono Québec

Community Involvement

  • Past board member, Centre for Addiction and Mental Health
  • Past board member, Nationals Arts Centre Foundation
  • Board of governors, Stratford Festival of Canada

Awards & Recognitions

  • Recognized as a leading energy lawyer in the 2013-2018 and 2020-2021 editions of the Lexpert® Special Edition — Canada’s Leading Energy Lawyers
  • Recognized in the 2021 edition of Best Lawyers in Canada as "Lawyer of the Year" (Administrative and Public Law, Appellate Advocacy)
  • Recognized in the 2021 (and since 2016) editions of Chambers Canada — Canada's Leading Lawyers for Business (Litigation: General Commercial; Dispute Resolution)
  • Consistently recognized in The Best Lawyers in Canada as Ottawa Administrative and Public Law - Lawyer of the Year and Ottawa Appellate Practice - Lawyer of the Year
  • Selected by peers for inclusion in the 2022 edition (and since 2006) of The Best Lawyers in Canada® (Administrative and Public Law; Appellate Practice; Class Action Litigation; Corporate and Commercial Litigation) and in 2022 (Railroad Law)
  • Recognized in the 2021 edition (and since 2013) of Chambers Global – The World’s Leading Lawyers for Business (Dispute Resolution: Litigation)
  • Recognized in the 2021 edition of Benchmark Canada – The Definitive Guide to Canada’s Leading Litigation Firms & Attorneys as a Local Litigation Star: Toronto and Ottawa
  • Recognized in the 2021 edition (and since 2013) of The Canadian Legal Lexpert® Directory (Litigation: Corporate Commercial; Litigation: Public Law; Litigation: Directors' and Officers' Liability; Class Actions; Litigation: Defamation & Media; Energy: Electricity; Energy: Oil and Gas)
  • Recognized in the 2020 edition of Lexpert Special Edition: Litigation
  • Recognized in the 2018 edition (and since 2013) of The Lexpert®/American Lawyer Guide to the Leading 500 Lawyers in Canada (Litigation: Corporate Commercial)
  • Recognized in the 2018 edition (and since 2014) of Legal 500 Canada (Dispute Resolution)
  • Recognized in the 2018 edition (and since 2013) of Benchmark Canada — The Definitive Guide to Canada's Leading Litigation Firms and Attorneys as one of the top 50 trial lawyers in Canada (Class Action: Constitutional; General Commercial)
  • Recognized by the 2018 Benchmark Canada Awards hall of fame lawyer of the year
  • Awarded the prestigious St. Yves Medal by Pro bono Québec in 2014
  • Recognized with a Lexpert® Zenith Award (pro bono team of the year — firm) in 2011 for the Réjean Hinse wrongful conviction civil lawsuit

Bar Admission & Education

  • Ontario, 1984
  • Québec, 2002
  • LLB, University of Toronto
  • MA (philosophy), University of Toronto
  • BA (Hons., Gold Medallist, history and philosophy), University of Western Ontario