Louisiana Purchase is a musical theater production from 1940. It has music and lyrics by Irving Berlin and book by Morrie Ryskind based on a story by B. G. DeSylva. In 1941 it was adapted for the film Louisiana Purchase directed by Irving Cummings.

The show opened at the Shubert Brothers' Imperial Theatre, New York City on May 28, 1940 and ran for 444 performances. It was produced by Buddy De Sylva, who also wrote the story, and staged by Edgar MacGregor. The musical orchestrations were by Robert Emmett Dolan and N. Lang Van Cleve, with the ballets by George Balanchine and the musical staging and dances by Carl Randall.

Set in New Orleans, the musical parodies Governor Huey Long and his control over Louisiana politics.

Louisiana Purchase is a 1941 film adaptation of the musical theatre play, Louisiana Purchase. A Paramount Pictures production, the film was directed by Irving Cummings with Robert Emmett Dolan serving as musical director as he had done for the play. Starring comedian Bob Hope, the film featured Vera Zorina, Victor Moore and Irène Bordoni reprising their stage roles. Raoul Pene Du Bois did the production and costume design and was nominated for the Academy Award for Best Art Direction-Interior Decoration, Color. The cinematography was by Harry Hallenberger and Ray Rennahan who also received a nomination for the Academy Award for Best Cinematography.

Graft is rampant in the government of a "mythical" Louisiana, and the arrival of U.S. Senate investigator Loganberry brings panic. The chief miscreants shift the blame on to their innocent tool, Jim Taylor, who to save himself must "compromise" the simon-pure Senator Loganberry. As his instrument, Jim selects Marina Von Minden, beautiful Viennese refugee. But matters become complicated when Jim falls for Marina... and she takes a liking for the Senator. Written by Rod Crawford