Paula White (as Miss Bessie Love)
Sir John Roxton (as Mr. Lewis S. Stone)
Prof. Challenger (as Mr. Wallace Beery)
Ed Malone (as Mr. Lloyd Hughes)
Gladys Hungerford (as Miss Alma Bennett)
Prof. Summerlee (as Mr. Arthur Hoyt)
Mrs. Challenger (as Miss Margaret McWade)
Ape-man (as Mr. Bull Montana)
Austin (as Mr. Finch Smiles)
Zambo (as Mr. Jules Cowles)
Colin McArdle (as Mr. George Bunny)
Maj. Hibbard (as Mr. Charles Wellsley)
Jocko - the Monkey (as Jocko)
Sir Arthur Conan Doyle
Mary - the Chimpanzee (uncredited)
Undetermined Secondary Role (uncredited)
Marquette - Half-Caste Girl (uncredited)
Old Professor (uncredited)
Lawyer Advising the Editor (uncredited)
Office Boy (uncredited)
Policeman (uncredited)
Percy Potts (uncredited)