Lon Chaney as Professor Echo / Grandma O'Grady

Lila Lee as Rosie O'Grady

Elliott Nugent as Hector McDonald

Harry Earles as Tweedledee aka Willie 'Midget'

John Miljan as Prosecuting Attorney

Ivan Linow as Hercules

Clarence Burton as Regan

Crauford Kent as Defense Attorney

Trixie Friganza as Lady Customer (uncredited)

Cecilia Parker as First Siamese Twin (uncredited)

Linda Parker as Second Siamese Twin (uncredited)

Ray Cooke as Sailor at Sideshow (uncredited)

Jack Baxley as Outside Sideshow Barker (uncredited)