The 1981 Canadian Grand Prix was a Formula One motor race held at Circuit Île Notre-Dame, Montreal on 27 September 1981. It was the fourteenth race of the 1981 Formula One World Championship.

The race was run in wet conditions, and ended after 63 of the scheduled 70 laps due to the two-hour time limit. Frenchman Jacques Laffite won in a Ligier-Matra, with Northern Ireland's John Watson second in a McLaren-Ford and local hero Gilles Villeneuve third in a Ferrari. Brazilian Nelson Piquet finished fifth in his Brabham-Ford, having started from pole position, while Drivers' Championship rival, Argentine Carlos Reutemann, could only manage tenth in his Williams-Ford. Piquet thus moved within one point of Reutemann with one race to go, while the win gave Laffite an outside chance of the title. Despite both Reutemann and Australian teammate Alan Jones failing to score, Williams clinched the Constructors' Championship.