Lady Be Good (title sometimes presented with an exclamation point) is the title of a Broadway musical play that was written by Guy Bolton, Fred Thompson, featured music by George and Ira Gershwin. It debuted in 1924.
It is a musical comedy about a brother and his sister who are out of money and each eager to sacrifice him- or herself to help the other. It originally starred brother and sister performers Fred Astaire and Adele Astaire. It ran for 330 performances in the original Broadway run.
The best known song from the score was "Oh, Lady be Good!".
Two films by this title were produced: a 1928 silent film and a 1941 film starring Eleanor Powell. Neither film were adapted from the stage play, although the songs "Oh, Lady Be Good!" and "Fascinating Rhythm are performed in the Powell film.