John Stephenson

as Grandpa Squirrel (voice)

as Professor Crackpotkin (voice)

as Professor Charles Xavier (voice)

as (voice)

as Doc / Philo / Gunge (voice)

as Jack Bennett 'Bionic-1' / Klunk (voices)

as Thundercracker / Windcharger / Huffer, Kup (voice)

as Klaus / Milo Damp (voice), Professor Busby / Olaf the Terrible (voice), Dr. LaRue (voice)

as (voice), Doctor Strange (voice), Colossus / Piotr Rasputin / Thunderbird / John Proudstar (voice)

as Mr. Slate

as Mildew Wolf / Dread Baron / Great Fondoo / Doggie Daddy (voice)

as Tom (voice)

as Colonel Wilcox (voice)

as Mr. Slate

as Stuart Wetherby / Ghost of Elias Kingston (voice), The Creeper (voice), Mr. Hyde / Dr. Jekyll (voice), Samson the Strongman (voice), Butler / C.L. Magnus / The Ghost of Redbeard (voice), The Mummy of Ankha (voice), The Black Knight / Museum Worker (voice), Big Bob Oakley / Dracula / Werewolf (voice), Sheriff / The Zombie (voice), Viking Puppet / Pirate Puppet (voice), Professor Wayne / The Caveman (voice), John Simms / The Witch Doctor / Mano Tiki Tia (voice)

as Blubber Bear (voice)

as Captain Leech (voice), Gulliver's Father /The King (voice)

as Number One (voice)

as Additional Voices

as Narrator (voice) (uncredited)

as Chief Winchley

as Dr. Quest (voice)

as Colonel Fuzzby

as Commissioner / DWMR Officer (voice), Gary Gammaray (voice), Dr. Scarem (voice)

as Fancy-Fancy (voice)