Unfaithful is a 2002 American erotic thriller film directed and produced by Adrian Lyne and written by Alvin Sargent and William Broyles Jr., adapted from the Claude Chabrol film The Unfaithful Wife (1969). Starring Richard Gere, Diane Lane, Olivier Martinez, and Erik Per Sullivan, the film follows Edward (Gere) and Connie Sumner (Lane), a couple living in the suburbs of New York City whose marriage is jeopardized when the wife has an affair with a stranger (Martinez) she encounters by chance.

Unfaithful was theatrically released in the United States on May 10, 2002, and was screened at the 37th Karlovy Vary International Film Festival on July 8, 2002. The film was a box office success, grossing $119.1 million against its $50 million production budget. Despite mixed reviews from critics, Lane received critical acclaim for her performance.

At the 7th Satellite Awards, Lane won for Best Actress in a Motion Picture, and was nominated for the Screen Actors Guild Award for Outstanding Performance by a Female Actor in a Leading Role at the 9th Screen Actors Guild Awards, the Golden Globe Award for Best Actress in a Motion Picture – Drama at the 60th Golden Globe Awards, and the Academy Award for Best Actress at the 75th Academy Awards, respectively.