Stars (in credits order)
Mark Hamill
James Marlowe Sr.
Roddy McDowall
Headmaster Marcus Howe
Nick Tate
Colony Leader
Pat Fraley
Willis
Marcia Mitzman Gaven
Dr. Jane Marlowe
Stanley Ralph Ross
Dr. "Mac" McRae
Benny Luciano
James "Jim" Marlowe Jr.
Haven Hartman
Phyllis Jane "P.J." Marlowe
Jess Harnell
Various Voices(uncredited)