Alexander's Ragtime Band is a 1938 American musical film released by 20th Century Fox that takes its name from the 1911 Irving Berlin song "Alexander's Ragtime Band" to tell a story of a society boy who scandalizes his family by pursuing a career in ragtime instead of "serious" music. The film generally traces the history of jazz music from the popularization of Ragtime in the early years of the 20th century to the acceptance of swing as an art form in the late 1930s using music composed by Berlin. The story spans more than two decades from the 1911 release of its name-sake song to some point in time after the 1933 release of "Heat Wave", presumably 1938.

It stars Tyrone Power, Alice Faye, Don Ameche, Ethel Merman, Jack Haley and Jean Hersholt. Several actual events in the history of jazz are fictionalized and adapted to the story including the tour of Europe by Original Dixieland Jass Band, the global spread of jazz by U.S. soldiers during World War I, and the 1938 Carnegie Hall performance by The Benny Goodman Orchestra.

The story was written by Berlin himself, with Kathryn Scola, Richard Sherman (1905–1962) and Lamar Trotti. In 1944, a federal judge ruled that most of the story by Berlin and collaborating writers had been plagiarized from a 1937 manuscript by author Marie Dieckhaus, but that decision was reversed on appeal.

Alexander's Ragtime Band was 20th Century Fox's highest-grossing film of the 1930s and was nominated for six Academy Awards, winning the award for Best Music, Scoring.