This is a photo of Leah Ostler




Contact by email at [email protected]

t. +1 416-601-8285


Law School

Osgoode Hall Law School

Bar Admission

Ontario, 2017

Leah Ostler is a litigator in our Litigation Group in Toronto. Her practice focuses on defence litigation, including the areas of privacy and cyber-security, commercial litigation, class actions and medical malpractice. Leah has served as junior counsel in trials, class actions, and before administrative tribunals in a wide range of complex matters. 

Leah is a key member of the McCarthy Cannabis Group. The Cannabis Group partners with clients driving the transformation of the recreational private retail sector, leveraging our knowledge of the industry and regulatory environment with extensive experience advising innovators in emerging markets. Our clients include major financial institutions, leading cannabis companies, commercial property holders, food and beverage producers, and more. Leah has specifically advised on cannabis use across the provinces, cannabis/hemp-derived CBD products under the Natural Health Products regime, US-Canada jurisdictional issues, and the Ontario Retail Regulations.

Leah received her J.D. from Osgoode Hall Law School, where she held executive positions with the Osgoode Women’s Network (OWN); was a Dean’s Fellow for Torts Law; volunteered with Osgoode’s Community & Legal Aid Services Program (CLASP); and lead several mentorship programs. Leah studied abroad at Amsterdam University, taking Masters of Laws courses in the subject of International Law. Leah obtained her B.A. (Honours) in History and Global Development from Western University and acted as a Political Intern for the Department of Foreign Affairs and International Trade (DFAIT) in Ramallah, West Bank. 


  • As a member of McCarthy’s International Arbitration Group, Leah co-wrote an article with Junior Sirivar on the topic of greater transparency in arbitration: The Mauritius Convention on Transparency: The Potential Impact on Canadian Investors, Commercial Litigation and Arbitration Review, Vol. 6 (23), August 2017
  • As a member of McCarthy’s Cannabis Group, Leah co-wrote an article with Ranjeev Dhillon on the Ontario Retail Regulations

Leah has co-authored several blogs and Legal Updates available on the McCarthy website.