Trans-Canada Air Lines (TCA) Flight 831 was a flight from Montréal–Dorval International Airport to Toronto International Airport on November 29, 1963. About five minutes after takeoff in poor weather, the jet crashed about 32 km (20 mi) north of Montreal, near Ste-Thérèse-de-Blainville, Quebec, Canada, killing all 111 passengers and seven crew members. The crash was the deadliest in Canadian history at the time. It was also the deadliest crash of a DC-8 at the time, and, as of 2022, the sixth-deadliest.

Trans-Canada Air Lines was a Canadian airline that operated as the country's flag carrier, with corporate headquarters in Montreal, Quebec. Its first president was Gordon Roy McGregor. Founded in 1937, it was renamed Air Canada in 1965.