Tannahill Lockhart & Clark Law LLP is a general practice law firm based in Mississauga that has served the Peel Region, including Brampton, Mississauga, and Caledon, since 1978. The firm focuses on wills and estates, civil litigation, estate litigation, real estate, and business law. Its lawyers include founding partners Douglas Tannahill and John Lockhart, along with associate Timothy Lockhart.

Practice areas

Wills, Estates & Trusts Civil Litigation & Dispute Resolution Personal Injury Real Estate Law Business & Corporate Law

Good to know

A person using a wheelchairWheelchair accessibleA rainbow pride heartLGBTQ+ friendly

Fees & payment

A clipboard with a speech bubble and a no-charge dollar coinFree consultation

Lawyers 3

Douglas D. Tannahill Senior Partner Business & Corporate LawReal Estate Law John S. Lockhart Senior Partner Civil Litigation & Dispute ResolutionWills, Estates & Trusts Timothy S. Lockhart Associate Civil Litigation & Dispute ResolutionReal Estate Law

This firm’s lawyers at a glance

Called to the bar
1975–2013 · median 49 years in practice 3 of 3 lawyers
Law schools
Bond University, Osgoode Hall Law School, University of Toronto 3 of 3 lawyers

Who handles what

Where to find them

5805 Whittle Rd, Unit 10, Mississauga, ON L4Z 2J1 · 905-502-5770

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