Heenan Blaikie

Heenan Blaikie LLP was a Canadian law firm. It practised in the areas of business, labour and employment, litigation, taxation, entertainment law and intellectual property law. The firm was founded in 1973 by Roy Heenan, Donald Johnston, and Peter Blaikie.

Based in Montreal, at one time the firm had over 500 lawyers at offices in Toronto, Ottawa, Calgary, Vancouver, Victoria, Quebec City, Sherbrooke, Trois-Rivières and Paris, with a representative office in Singapore and a satellite office in Los Angeles. As of February 2011, it was the sixth largest law firm in Canada. It became the largest law firm to close in Canadian history after its partners voted to dissolve the firm on 5 February 2014. The firm closed on 28 February 2014.

The firm was involved in Canada's longest lawsuit, related to the bankruptcy of a finance company named Castor Holdings. Widdrington Estate v. Wightman lasted more than 12 years, about 20 times as long as originally predicted. The firm closed shortly after its resolution.