Black Christmas is a 1974 Canadian slasher film produced and directed by Bob Clark, and written by A. Roy Moore. It stars Olivia Hussey, Keir Dullea, Margot Kidder, Andrea Martin, Marian Waldman and John Saxon. The story concerns a group of sorority sisters who receive threatening phone calls and are eventually stalked and murdered by a deranged killer during the Christmas season. It is the first film in the Black Christmas film series.

Inspired by the urban legend “The babysitter and the man upstairs” and a series of murders that took place in the Westmount section of Montreal, Quebec, Moore wrote the screenplay under the title Stop Me. The filmmakers made numerous alterations to the script, primarily the shifting to a university setting with young adult characters. It was shot in Toronto in 1974 on an estimated budget of $620,000, and was distributed by Warner Bros. in North America.

Black Christmas was released on October 11, 1974 in Canada (the very same day as another horror classic, The Texas Chain Saw Massacre), and December 20 in the United States under the title Silent Night, Evil Night. Upon its release, the film received mixed reviews but has since received critical praise, with film historians noting it for being one of the earliest slasher films. It is also praised for concluding without revealing the identity of its villain, as well as serving as an influence on John Carpenter’s Halloween (1978). Aside from earning a cult following since its release, a novelization written by Lee Hays was published in 1976.