Polygraph (French: Le Polygraphe) is a film by Canadian director Robert Lepage, released in 1996.

The film stars Marie Brassard as Lucie Champagne, an actress who is given the role of Marie-Claire in a film dramatizing a real-life murder, and Patrick Goyette as François, Lucie's former boyfriend who was Marie-Claire's neighbour, remains a suspect in the real crime to the point that even he is no longer fully convinced that he is innocent, and is being pressured to play the killer in the film. The film's cast also includes Josée Deschênes, Maria de Medeiros, Peter Stormare, Marie-Christine Lê-Huu and Richard Fréchette.

The film was inspired in part by the 1979 murder of France Lachapelle, an actress in Quebec City who had been a friend and colleague of Lepage's, with the result that Lepage discovered her body and was actually the police investigator's initial suspect before being cleared, and filmmaker Yves Simoneau's subsequent request that Lepage play the killer in Red Eyes (Les Yeux rouges), his 1982 film dramatizing the incident.