The Exorcist is a 1973 American supernatural horror film directed by William Friedkin from a screenplay by William Peter Blatty, based on his 1971 novel. The film stars Ellen Burstyn, Max von Sydow, Jason Miller, and Linda Blair, and follows the demonic possession of a young girl and the attempt to rescue her through an exorcism by two Catholic priests.

Blatty, who also produced, and Friedkin, his choice as director, had difficulty casting the film. Their choice of relative unknowns Burstyn, Blair, and Miller, instead of major stars, drew opposition from executives at Warner Bros. Principal photography was also difficult. Many cast and crew were injured, some died, and unusual accidents delayed shooting. Production took twice as long as scheduled and cost almost three times the initial budget; the many mishaps have led to a belief that the film was cursed.

The Exorcist was theatrically released in the United States on December 26, 1973, by Warner Bros., and in the United Kingdom on March 14, 1974, by Columbia Pictures through Columbia-Warner Distributors. Reviews were mixed, but audiences waited in long lines during cold weather; the sold-out shows were even more profitable for Warner Bros., who had booked it into those theaters under four wall distribution rental agreements, the first time a major studio had done that. Some viewers suffered adverse physical reactions, fainting or vomiting to shocking scenes such as a realistic cerebral angiography. Many children were allowed to see it, leading to charges that the Motion Picture Association of America (MPAA) had accommodated the studio by giving the film an R rating instead of an X rating to ensure the troubled production its commercial success. Several cities attempted to ban it outright or prevent children from attending. At the end of its original theatrical run, the film grossed $193 million, and has a lifetime gross of $441 million with subsequent re-releases.

The cultural conversation around the film helped it become the first horror film to be nominated for the Academy Award for Best Picture, as well as nine others. Blatty won Best Adapted Screenplay, while the sound engineers took Best Sound. It has had several sequels and was the highest-grossing R-rated horror film (unadjusted for inflation) until 2017's It. The Exorcist significantly influenced pop culture, and several publications regard it as one of the greatest films ever made. In 2010, the Library of Congress selected the film for preservation in the United States National Film Registry as being "culturally, historically, or aesthetically significant".