Black Christmas is a 1974 independent Canadian horror film 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 follows college students who must face a deranged serial killer lurking in their sorority house. It was inspired by the urban legend of "The Babysitter and the Man Upstairs", but was also largely based on a series of murders that took place in Quebec, Canada around Christmas time.
Black Christmas is generally considered to be one of the first slasher films.