Lawyers Directory

Thomas McDonnell, Q.C.

Toronto Office
(416) 864-0077

Thomas McDonnell, Q.C. is associated with the firm’s Toronto office, as counsel.

During a distinguished career in taxation, Thomas has counseled private and public sector clients on a wide range of matters involving domestic and international tax issues, and has consulted on tax matters for the federal departments of Finance, Justice and Revenue, and the Auditor General of Canada. He is a member of the firm’s High Net Worth Individual Practice Group.

He holds a Bachelor of Arts degree (economics) from the University of Toronto and a Bachelor of Law degree from Osgoode Hall Law School. A member of the Ontario Bar since 1967, he was appointed Queen’s Counsel in 1984. Thomas was awarded the Queen’s Jubilee Medal in 2012 in recognition of his contributions to Canada.

Thomas taught tax and business law as a member of the teaching faculty at the University of Toronto Law School, 1974-1977; was a member of the Joint Committee on Taxation of the Canadian Bar Association and the Canadian Institute of Chartered Accountants, 1976-1982; served as the chairman of the Working Group on the Corporate Minimum Tax (Ontario), 1991-1992; and was the Executive Director of the Canadian Tax Foundation, June 1, 1994- December 31, 1995.

Thomas is perhaps best known to members of the tax community as a past editor of the “Current Cases” feature in the Canadian Tax Journal, a position he held for 17 years. He is a member of the Editorial Review Board of the Canadian Tax Foundation and the editor of its newsletter “Taxation for the Owner/Manager of Private Businesses.” He is a co-author of “Scientific Research and Experimental Development: a Practical Guide” (CCH Canadian, Toronto, Second Edition 2001), and is currently working on “Effective Writing for Tax Professionals,” a book to be published by the Canadian Tax Foundation in 2013.

He has lectured on tax matters for the Canadian Institute of Chartered Accountants, the Canadian Bar Association, the Canadian Tax Foundation, the International Bar Association, the Law Society of Upper Canada, the Canada Revenue Agency, and a number of law schools and private continuing education organizations. His articles on taxation have been published by the Canadian Tax Foundation, The International Business Lawyer, The Australian Tax Journal, private educational associations, and newspapers. He blogs regularly on tax matters at