The Magnificent Yankee is a 1950 American biographical film adapted by Emmet Lavery from his 1946 play of the same title, which was in turn adapted from the 1942 book Mr. Justice Holmes by Francis Biddle. The story examines the life of United States Supreme Court Justice Oliver Wendell Holmes Jr.

The film was directed by John Sturges, with stars Louis Calhern, Ann Harding, Eduard Franz, and Philip Ober. Calhern created the role of Oliver Wendell Holmes in the original Broadway production. Calhern began as a leading man in silent films but became primarily a character actor with the arrival of the sound era. His portrayal of Holmes was his only true starring role in a sound film. A grateful Metro-Goldwyn-Mayer purchased the film rights to the play specifically for Calhern in appreciation for his consistently fine work in many supporting roles during his years with the studio.

The film was nominated for Academy Awards for Best Actor in a Leading Role (Louis Calhern) and Best Costume Design, Black-and-White.

A Hallmark Hall of Fame television production of the same title was broadcast in 1965 starring Alfred Lunt and Lynn Fontanne.