The Bells of St. Mary's is a 1945 American drama film produced and directed by Leo McCarey and starring Bing Crosby and Ingrid Bergman. Written by Dudley Nichols based on a story by Leo McCarey, the film is about a priest and a nun who, despite their good-natured rivalry, try to save their school from being shut down. The character of Father O'Malley had been previously portrayed by Crosby in the 1944 film Going My Way, for which Crosby had won the Academy Award for Best Actor. The film was produced by Leo McCarey's production company, Rainbow Productions.

The Bells of St. Mary's may refer to:

• The Bells of St. Mary's (1937 film), a 1937 British film, starring John Garrick, released by MGM's UK division
• The Bells of St. Mary's, a 1945 film
• The Bells of St. Mary's (1959 film), a 1959 made-for-television film
• "The Bells of St. Mary's" (song), a popular song