Bessie Love
as Miss Paula White
Lloyd Hughes
as Edward E. Malone
Wallace Beery
as Professor Challenger
Lewis Stone
as Sir John Roxton
Jules Cowles
as Zambo, Roxton's Servant)
Arthur Hoyt
as Professor Summerlee
Bull Montana
as Montana
Nelson McDowell
as Lawyer advising the editor (uncredited)
Margaret McWade
as Mrs. Challenger
Frank Finch Smiles
as Austin, Challenger's Butler
Alma Bennett
as Gladys Hungerford
Virginia Brown Faire
as Marquette (half-caste girl) (uncredited)