...One Third of a Nation... is a 1939 American drama film directed by Dudley Murphy and written by Oliver H.P. Garrett and Dudley Murphy. The film stars Sylvia Sidney, Leif Erickson, Myron McCormick, Hiram Sherman, the future director Sidney Lumet and Muriel Hutchison. The film was released on February 10, 1939, by Paramount Pictures.

Sylvia Sidney was an American stage, screen, and film actress whose career spanned 70 years. She rose to prominence in dozens of leading roles in the 1930s. She was nominated for the Academy Award for Best Supporting Actress for her performance in Summer Wishes, Winter Dreams in 1973. She later gained attention for her role as Juno, a case worker in the afterlife, in Tim Burton's 1988 film Beetlejuice, for which she won a Saturn Award for Best Supporting Actress.