A Letter to Three Wives is a 1949 American romantic comedy-drama which tells the story of a woman who mails a letter to three women, telling them she has left town with the husband of one of them, but not saying which one. It stars Jeanne Crain, Linda Darnell, Ann Sothern, Paul Douglas (in his film debut), Kirk Douglas, and Jeffrey Lynn. Thelma Ritter as "Sadie" and Celeste Holm (the voice of "Addie Ross", the unseen woman who wrote the letter) are both uncredited.

The film was adapted by Vera Caspary and written for the screen by Joseph L. Mankiewicz from A Letter to Five Wives, a story by John Klempner that appeared in Cosmopolitan, based on a 1945 novel by Klempner. It was directed by Mankiewicz, who directed All About Eve the following year.

The film won the Academy Awards for Best Director and the Best Adapted Screenplay and was nominated for Best Picture.