Friday the 13th is a 1980 American independent horror film directed by Sean S. Cunningham and written by Victor Miller. The film stars Betsy Palmer, Adrienne King, Harry Crosby and Kevin Bacon in one of his earliest roles. The film concerns a group of teenagers who re-open an abandoned camp site years after a young boy drowned in a lake located nearby. One by one, the teens fall victim to a mysterious killer.

Friday the 13th, inspired by the success of John Carpenter's Halloween, was made on an estimated budget of $550,000. Released by Paramount Pictures in the United States, and Warner Bros. internationally, the film was poorly received by film critics, but grossed over $39.7 million at the box office in the United States, and went on to become one of the most profitable slasher films in cinema history. It was also the first movie of its kind to secure distribution in the USA by a major studio, Paramount Pictures. The film's box office success led to a long series of sequels, a crossover with Freddy Krueger and a series reboot released on February 13, 2009.

The film begins in 1958 as two summer camp counselors at Camp Crystal Lake sneak away from a campfire sing-along to have sex. Before they can completely undress, an unseen assailant sneaks into the room and murders them both. The film then moves forward to Friday, June 13, in the present day; a young woman named Annie (Robbi Morgan) enters a small diner and asks for directions to Camp Crystal Lake, much to the shock of the restaurant's patrons and staff. A strange old man named Ralph (Walt Gorney) reacts to the news of the camp's reopening by warning Annie that they are "all doomed".