"You Don't Know What Love Is" is a popular song of the Great American Songbook, written by Don Raye (lyrics) and Gene de Paul (music) for the Abbott and Costello film Keep 'Em Flying (1941), in which it was sung by Carol Bruce. The song was deleted from the film prior to release. The song was later included in Behind the Eight Ball (1942), starring the Ritz Brothers. "You Don't Know What Love Is" was again sung by Carol Bruce; it was her third and final film until the 1980s.