LAWYER PROFILE
Mark Tonkovich

Mark Tonkovich

Global 2026

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Ranked in 1 practice area

About

Provided by Blake, Cassels & Graydon LLP

Practice Areas

Mark Tonkovich co-leads Blakes’ national Tax Controversy and Litigation group. His practice focuses exclusively on resolving Canadian tax disputes. He represents many of Canada’s and the world’s largest and most sophisticated businesses in tax-related civil litigation, administrative appeals, audit defence, and in proactively managing tax controversy risks. Mark has successfully acted for taxpayers at all levels of court, with the Federal Court of Appeal describing his work as ""exemplary"" in a 2013 judicial review application. He draws on Blakes' top-tier national tax practice to develop and execute comprehensive and practical strategies for resolving tax disputes as efficiently and favourably as possible, both within and beyond the courtroom.

Mark frequently writes and presents on tax issues for professional and industry organizations. He is a member of the Federal Courts Bench and Bar Liaison Committee and the editorial board of the journal Tax Litigation, and he previously chaired the Tax Court Bench and Bar Committee and the Ontario Bar Association’s Taxation Law Section. He has written dozens of articles on Canadian tax matters, including in the peer-reviewed Canadian Tax Journal and the National Journal of Constitutional Law. Earlier in his career, Mark was an appellate judicial clerk and a tax litigator with the Department of Justice.

Chambers Review

Provided by Chambers

Chambers Global Guide

Tax: Litigation - Canada

Band 2
Band 2

Individual Editorial

Toronto-based Mark Tonkovich represents clients in high-profile tax enforcement and litigation files. He has worked on several longstanding disputes with the Canada Revenue Agency. He coleads Blake, Cassels & Graydon's tax controversy and litigation group.

Strengths

Provided by Chambers

  • Mark is a wonderful individual to work with and demonstrates a very client-centric focus.

    Tax: LitigationChambers Global Guide
  • He is very responsive and able to walk us through complex tax matters.

    Tax: LitigationChambers Global Guide
  • Mark is spectacular. He is very practical, reasonable and meticulous.

    Tax: LitigationChambers Global Guide
  • Mark combines thoroughness and technical expertise with a personable and approachable manner. He continues to demonstrate a clear dedication towards achieving desired outcomes for his clients.

    Tax: LitigationChambers Global Guide
  • Mark provides practical advice and has a strong ability to see the business side of the argument, in addition to the technical side.

    Tax: LitigationChambers Global Guide

Ranked Individuals at Blake, Cassels & Graydon LLP (92)

Canada

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