Supergirl is a 1984 superhero film directed by Jeannot Szwarc from a screenplay by David Odell based on the DC Comics character of the same name. It is the fourth film in the Superman film series, set after the events of Superman III (1983) and serving as a spin-off of the series. The film stars Helen Slater as Supergirl, along with Faye Dunaway, Hart Bochner, Peter Cook, Mia Farrow, Brenda Vaccaro, and Peter O'Toole, with Marc McClure reprising his role as Jimmy Olsen from the Superman films.

The film was released in the United Kingdom on 19 July 1984 and in the United States on 21 November 1984, but failed to impress either critics or audiences, while also underperforming at the box-office. Dunaway and O'Toole earned Golden Raspberry Award nominations for Worst Actress and Worst Actor, respectively. Slater was nominated for a Saturn Award for Best Actress. The film's failure ultimately led producers Alexander and Ilya Salkind to sell the Superman film rights to The Cannon Group, Inc. in 1986.

Its first DVD release was by the independent home video company Anchor Bay Entertainment in 2000, under license from then-rights holder StudioCanal. Warner Bros. Pictures acquired the rights to the film and reissued it on DVD late in 2006 to coincide with the release of Superman Returns. Although it is canon with the Christopher Reeve Superman films, it is not included in any of the Superman DVD or Blu-ray box sets by Warner Bros.