The Slumber Party Massacre (also known as The Slumber Party Murders in the United Kingdom) is a 1982 American slasher film produced and directed by Amy Jones and written by Rita Mae Brown. It is the first installment in the Slumber Party Massacre series, and stars Michelle Michaels, Robin Stille, and Michael Villella. The film follows a high school senior who gathers her friends for a slumber party, unaware that an escaped power drill-wielding killer is loose in the neighborhood.

The film was originally written by Brown as a parody of the slasher genre but was shot as a straightforward horror film instead. As a result, it contains more humor, both intended and unintended, than usual for the genre at the time.

The Slumber Party Massacre grossed $3.6 million at the box office on a budget of $220,000, and received mixed reviews from critics. Despite the reception, it has obtained a large cult following since its release. Two direct sequels, Slumber Party Massacre II and Slumber Party Massacre III, followed in 1987 and 1990, respectively, with a fourth film following in 2021. Two spin-off film series forming a wider Massacre franchise were also produced: the Sorority House Massacre trilogy (1986–1990), and the Cheerleader Massacre films (2003–2011), the first film of the latter series having been filmed as Slumber Party Massacre 4 before being renamed.