William LeBaron (February 16, 1883 – February 9, 1958) was an American film producer, lyricist, librettist, playwright, and screenwriter.

LeBaron authored several plays for Broadway; including the books and lyrics for several musicals in addition to non-musical works staged in New York City between 1911 and 1925. Some of these plays were adapted into films; including his 1917 play The Very Idea, which was made into a silent film in 1920 and a talking picture in 1929; and his 1921 play Nobody's Money, which was adapted into a film in 1923. He also authored the libretti to operettas composed by Victor Herbert, Emmerich Kálmán, Fritz Kreisler and Victor Jacobi.

By 1926 LeBaron had relocated from New York City to Los Angeles, and was thereafter predominantly active as a film producer. His film credits included Cimarron, which won the Academy Award for Outstanding Production at the 4th Academy Awards ceremony for 1930/1931. LeBaron also produced landmark comedy features from W. C. Fields, Mae West and Wheeler and Woolsey. In addition to being a producer, LeBaron served as the last production chief of Film Booking Offices of America and at FBO's successor, RKO Pictures, where he was replaced by David O. Selznick.