Halloween (advertised as John Carpenter's Halloween) is a 1978 American independent slasher film directed and scored by John Carpenter, who co-wrote it with its producer Debra Hill. It stars Donald Pleasence, Jamie Lee Curtis (in her film debut), P. J. Soles, and Nancy Loomis. Set mostly in the fictional Illinois town of Haddonfield, the film follows mental patient Michael Myers, who was committed to a sanitarium for murdering his teenage sister one Halloween night during his childhood; he escapes 15 years later and returns to Haddonfield, where he stalks teenage babysitter Laurie Strode and her friends while his psychiatrist Dr. Samuel Loomis pursues him.

The film was shot in Southern California throughout May 1978, produced by Compass International Pictures and Falcon International Productions. The film was released by Compass International and Aquarius Releasing in October and grossed $70 million on a budget of $300,000, becoming one of the most profitable independent films of all time. Primarily praised for Carpenter's direction and score, many critics credit the film as the first in a long line of slasher films inspired by Psycho (1960), The Texas Chain Saw Massacre and Black Christmas (both 1974). It is considered one of the greatest and most influential horror films ever made. In 2006, it was selected for preservation in the United States National Film Registry by the Library of Congress as being "culturally, historically, or aesthetically significant".

Halloween spawned a film franchise comprising 13 films which helped construct an extensive backstory for Michael Myers, sometimes narratively diverging entirely from previous installments; a novelization, video game, and comic book series have also been based on the film.