The Fan is a 1981 American psychological thriller film directed by Edward Bianchi and starring Lauren Bacall, Michael Biehn, James Garner, and Maureen Stapleton. The plot follows a famous stage and film actress named Sally Ross (Bacall) who is stalked by a violent, deranged fan (Biehn), who begins killing those around her. The screenplay by Priscilla Chapman and John Hartwell was based on the 1977 novel by Bob Randall.

Development of The Fan began in 1979, and several iterations of the screenplay were produced by a number of writers before Chapman and Hartwell's version was finalized. Filmways initially offered to co-produce and distribute the film, offering to pay for the majority of its production budget. However, after its completion in 1980, Filmways backed out of the project due to their studio's experiencing financial troubles, after which Paramount Pictures acquired distribution rights.

The Fan was released in the United States on May 15, 1981, and was a box-office bomb, grossing $3.1 million. It received largely unfavorable reviews from film critics, though it would later acquire a cult following in the years after its release. Though Bacall was publicly critical of the film after its release, she later reflected that she felt her performance in it was among her best work.