Thomasina A. Dumonceau

P: 416-593-2999
F: 416-594-3527
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  • Called to the Bar of Ontario, 2002
  • LL.B., University of Toronto, 2000
  • B.A., (Honours) International Studies, University of Saskatchewan, 1997
Thomasina Dumonceau Photo ©2021 Blaney McMurtry LLP

Thomasina’s litigation practice focuses on defending professionals in errors and omission claims, including financial advisors, appraisers, lawyers, engineers, insurance and mortgage brokers, and various health professionals (nurses, massage therapists, physiotherapists, psychologists, social workers and speech pathologists to name a few).
For over two decades, clients have relied on Thomasina’s strong analytical skills and pragmatic approach to litigation to achieve favourable results in a cost-effective manner. Known for her attention to detail and her ability to drill down to the essential facts and issues of a case, Thomasina has experience handling complex, multi-party claims.
Beyond her expertise with professional liability claims, Thomasina also handles a wide variety of commercial and general liability claims, D&O claims, environmental claims, as well as life and disability claims.
Thomasina’s practice also includes representing various health professionals in professional regulation matters, including College complaints, investigations, and discipline hearings, as well as representing financial advisors in FSCO and MFDA proceedings.
An active advocate, Thomasina has defended claims throughout Ontario and has appeared before the Superior Court of Justice, the Ontario Divisional Court, the Ontario Court of Appeal, as well as before multiple regulatory bodies and professional Colleges.

  • LL.B., University of Toronto, 2000
  • B.A., (Honours) International Studies, University of Saskatchewan, 1997
 Practice Areas  Called to the Bar
  • Called to the Bar of Ontario, 2002


  • Recognized in Best Lawyers® in Canada 2024 for Insurance Law 


  • Law Society of Ontario
  • Ontario Bar Association
  • Professional Liability Underwriting Society
  • Canadian Defence Lawyers


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