Madman is a 1981 American slasher film written and directed by Joe Giannone and starring Gaylen Ross and Paul Ehlers. The plot focuses on an axe-wielding murderer named Madman Marz who, after accidentally being summoned by a group of campers during a campfire tale, begins to stalk and murder the young adults.

Originally based on the upstate New York urban legend of the Cropsey maniac, the film was conceived by Giannone and producer Gary Sales, both first-time feature filmmakers who had met in college. Their initial premise and main antagonist was changed last-minute due to conflicts with The Burning (1981), which featured the Cropsey villain and was in production at the same time.

Madman was given a regional platform release by Jensen Farley Pictures, opening in Albuquerque, New Mexico on October 30, 1981, and screening throughout the United States over the following two years. It received largely unfavorable reviews from critics, though it became a sleeper hit in the drive-in theater circuit in the United States. Though not prosecuted for obscenity nor officially listed as a video nasty, the film was seized by police forces in Hampshire, England during the video nasty panic.

In the years since its release, Madman has achieved a cult following. In 2017, it was named one of the greatest slasher films of all time by Complex magazine.