A Foreign Affair is a 1948 American romantic comedy-drama film directed by Billy Wilder and starring Jean Arthur, Marlene Dietrich, and John Lund. The screenplay by Wilder, Charles Brackett, and Richard L. Breen is based on a story by David Shaw adapted by Robert Harari.

The film is about a United States Army captain in post-World War II Berlin, occupied by the Allies during the early days of the Cold War, who is torn between an ex-Nazi cafe singer and the United States congresswoman investigating her. Though a comedy, the film has a serious and cynical political tone, attesting to the fascination of both Wilder and American audiences with the multiple legacies of Berlin.