About Thorsteinssons LLP

Thorsteinssons LLP is a Canadian law firm that practices exclusively in tax law, headquartered in Vancouver with a second office in Toronto. Paterson (Pat) Thorsteinsson, QC, one of the country's first tax lawyers, founded the firm in Vancouver in 1964 after returning to British Columbia. The firm describes itself as Canada's largest law firm working exclusively in tax law and its only national tax law firm, and it opened a Toronto office in 1990 to serve a growing base of clients across the country.

The firm's lawyers handle tax planning and corporate restructuring, tax litigation, international taxation, GST, HST and other sales taxes, customs and trade, and tax related criminal defence, along with estate planning and work for tax exempt organizations and investment funds. Thorsteinssons lawyers have appeared in landmark Supreme Court of Canada tax cases, including Canada v. Loblaw Financial Holdings Inc. and Canada v. Alta Energy Luxembourg S.A.R.L., both decided in 2021, as well as earlier cases such as Daishowa-Marubeni International Ltd. v. Canada.

Practice areas

Tax Law

Milestones & recognition

  • Paterson (Pat) Thorsteinsson, QC, a member of the University of British Columbia's law class of 1951 and one of the country's first tax lawyers, founded the firm in Vancouver in 1964.
  • The firm opened its Toronto office in 1990, expanding beyond British Columbia for the first time.
  • Thorsteinssons donated $125,000 to the University of British Columbia's Allard School of Law building project, and a group study room in the new law building was named in recognition of the gift.
  • Firm lawyers have appeared in Supreme Court of Canada tax cases including Canada v. Loblaw Financial Holdings Inc. and Canada v. Alta Energy Luxembourg S.A.R.L., both decided in 2021.
  • Best Lawyers has recognized Thorsteinssons lawyers with dozens of individual awards in its Best Lawyers in Canada guide and named the firm among its Best Law Firms in Canada for tax law.

In the community

  • The firm publishes a tax law blog covering federal and provincial developments, including posts on the Canada Revenue Agency's audit powers and changes to Canadian sales tax rules such as HST, GST, and BC's provincial sales tax.

Good to know

A person using a wheelchairWheelchair accessibleA laptop showing a video callVirtual appointmentsA calendar with a checkmark beside a clockBy appointmentAn office interior with a desk and chairsIn-person services

Lawyers 70

Adrian Zee Associate Tax Law Alexander Barnes Associate Tax Law Alexander Demner Partner Tax Law Alexei Paish Associate Tax Law Asif Abdulla Partner Tax Law Brandon Wiener Partner Tax Law Brendan Forrest Partner Tax Law Brent Pidborochynski Partner Tax Law Brittany Rossler Partner Tax Law Charlotte Tan Associate Tax Law Chris Canning Partner Tax Law Colin Smith Partner Tax Law Daniel Sze Associate Tax Law David Baxter Partner Tax Law David Christian Partner Tax Law David Davies Partner Tax Law David Thompson Partner Tax Law E. Rebecca Potter Partner Tax Law Elizabeth Egberts Associate Tax Law Elliott Simpson Associate Tax Law Eryn Fanjoy Partner Tax Law Florence Sauve Partner Tax Law Genna Wood Associate Tax Law Gloria Wang Partner Tax Law

This firm’s lawyers at a glance

Called to the bar
1984–2024 · median 19 years in practice 21 of 70 lawyers
Law schools
University of British Columbia (13), University of Toronto (8), University of Western Ontario (6), Osgoode Hall Law School (5), University of Ottawa (5), University of Victoria (5) and 12 more 59 of 70 lawyers
Languages on the roster
Cantonese, Chinese, English, French, Mandarin, Mandarin Chinese, Spanish

Who handles what

Offices 2

Toronto416-864-0829

PO Box 786, 33rd Floor, Brookfield Place, Bay Wellington Tower, 181 Bay St., Toronto, ON M5J 2T3

Vancouver604-689-1261

Suite 2600 - 1090 West Pender Street, Vancouver, BC V6E 0E3

The neighbourhood

Thorsteinssons' Toronto office is on the 33rd floor of the Bay Wellington Tower at 181 Bay Street, one of the two towers that make up Brookfield Place in the Financial District. The complex connects into the underground PATH network and includes the Allen Lambert Galleria, a six storey glass atrium designed by Santiago Calatrava, along with 12 preserved heritage buildings. One of those heritage buildings, a restored 1885 Bank of Montreal branch at Yonge and Front, now houses the Hockey Hall of Fame.

That's a downtown financial district address, not the firm's home base. Thorsteinssons was founded in Vancouver in 1964 and remains headquartered there. The Toronto office came later, opening in 1990 to give the firm a Bay Street presence for clients in Ontario and across Central Canada.

Frequently asked questions

Is Thorsteinssons based in Toronto?
No. Thorsteinssons is headquartered in Vancouver, where it was founded in 1964. The Toronto office, on the 33rd floor of the Bay Wellington Tower at 181 Bay Street, opened later, in 1990, to serve clients in Ontario and across Central Canada.
What kind of law does Thorsteinssons practice?
Tax law only. The firm handles corporate tax planning and restructuring, tax litigation, international taxation, GST, HST and other sales taxes, customs and trade, tax exempt organizations, investment funds, estate planning, and tax related criminal defence.
I'm being audited or reassessed by the CRA. Can Thorsteinssons help?
Yes. The firm's taxpayer representation practice handles disputes with the Canada Revenue Agency and provincial tax authorities, and its lawyers appear before the Tax Court of Canada, the Federal Court of Appeal, and the Supreme Court of Canada.
My business imports or exports goods. Does the firm handle customs and trade law?
Yes. Thorsteinssons advises on customs valuation, tariff classification, and import and export permits through its customs and international trade practice.
Does anyone at the firm speak Mandarin?
Yes. A partner in the firm's Vancouver office, who focuses on commodity tax matters such as GST and HST, is fluent in Mandarin Chinese.
How long has Thorsteinssons been practicing tax law?
Since 1964, when Paterson (Pat) Thorsteinsson founded the firm in Vancouver. It's been a tax only practice for more than 60 years.

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Listing compiled from the firm’s public website in September 2026. Verify licence status in the Law Society of Ontario directory ↗