Bessie Love as Paula White

Lewis Stone as Sir John Roxton

Wallace Beery as Prof. Challenger

Lloyd Hughes as Edward E. Malone

Alma Bennett as Gladys Hungerford

Arthur Hoyt as Prof. Summerlee

Margaret McWade as Mrs. Challenger

Bull Montana as Ape Man

Frank Finch Smiles as Challengers Diener

Jules Cowles as Zambo

George Bunny as Colin McArdle

Charles Wellesley as Maj. Hibbard

Arthur Conan Doyle as Himself

Virginia Brown Faire as Marquette

Nelson McDowell as Lawyer

Gilbert Roland as Extra

Leo White as Percy Potts