Body Double is a 1984 American neo-noir erotic thriller film directed, co-written, and produced by Brian De Palma. It stars Craig Wasson, Gregg Henry, Melanie Griffith, and Deborah Shelton. The film is a direct homage to the 1950s films of Alfred Hitchcock, specifically Rear Window, Vertigo, and Dial M for Murder, taking plot lines and themes (such as voyeurism, panic attack and obsession) from the first two.

At the time of its release, the film was a commercial failure, earning $8.8 million at the box office against a production budget of $10 million, as well as mixed reviews, though Griffith's performance earned praise and earned her a nomination for the Golden Globe Award for Best Supporting Actress – Motion Picture. Subsequently, the film received positive appraisal from cinema fans and is now considered to be a cult film.

Struggling actor Jake Scully has recently lost his role as a vampire in a low-budget horror film after his claustrophobia thwarts shooting. Upon returning home to discover his girlfriend cheating on him, Scully splits up with her and is left homeless. At a method acting class, where he meets Sam Bouchard, Scully reveals his fears and the childhood cause of his claustrophobia. They go to a bar where Scully is offered a place to stay; Sam's rich friend has gone on a trip to Europe and needs a house-sitter for his ultra-modern home in the Hollywood Hills.

While touring the house with Scully, Sam is especially enthusiastic about showing him one feature: a telescope, and through it a female neighbor, Gloria Revelle, who erotically dances at a specific time each night. Scully voyeuristically watches Gloria until he sees her being abused by a man she appears to know. The next day, he follows her when she goes shopping. Gloria makes calls to an unknown person whom she promises to meet. Scully also notices a disfigured "Indian", a man he had noticed watching Gloria a few days prior.

Scully follows Gloria to a seaside motel where she is apparently stood up by the person she was there to meet. On the beach, the Indian suddenly appears and snatches her purse. Scully chases him into a nearby tunnel, but his claustrophobia overcomes him. Gloria walks him out of it, and they impulsively and passionately kiss before she retreats. That night, Scully again is watching through the telescope when the Indian returns and breaks into Gloria's home. Scully races to save Gloria, but her vicious white German Shepherd attacks him, and the Indian murders Gloria with a huge handheld drill.

Scully alerts the police, who rule the murder a botched robbery. However, Detective Jim McLean becomes suspicious after finding a pair of Gloria's panties in Scully's pocket. Although McLean does not arrest him, he tells Scully that his voyeuristic behavior and failure to alert police sooner helped cause Gloria's death. Later that night, suffering from insomnia and watching a pornographic television channel, Scully sees porn actress Holly Body dancing sensually, exactly as Gloria did. In order to meet Holly, he is hired as a porn actor in Holly's new film.

Scully learns from Holly that Sam hired her to impersonate Gloria each night, dancing in the window, knowing Scully would be watching and later witness the real Gloria's murder. Offended when he suggests she was involved in a killing, Holly storms out of the house. An older man in a Ford Bronco picks her up, knocks her unconscious and drives away with her.

Scully follows them to a reservoir where the man is digging a grave. Scully attacks him, and in the scuffle peels his face off to reveal it as a mask worn by Sam (who also disguised himself as the "Indian" earlier). Scully has been set up as a scapegoat by Sam, who is in fact Gloria's abusive husband Alex, to provide him with an alibi during the murder. Scully is overpowered and thrown into the grave. Though his claustrophobia initially incapacitates him again, he overcomes his fear and climbs out, and Sam is knocked into the aqueduct by Gloria's white German Shepherd and drowned.