L'emmerdeur (literally The Troublemaker, with the English title of A Pain in the Ass, often promoted as A Pain in the A__) is a 1973 French-Italian black comedy film, starring Jacques Brel, appearing in his tenth and final feature film. Directed by Édouard Molinaro and co-starring Lino Ventura, Caroline Cellier, and Jean-Pierre Darras, L'emmerdeur is an adaptation of Francis Veber's 1971 play Le contrat.

In the film, a contract killer waits for his intended victim at a hotel room, but his plan is accidentally thwarted by the suicidal salesman occupying the neighboring room. He resorts to prevent the salesman from committing suicide, in fear that the suicide would cause a police search in the hotel.