Rex (voice)
Jeremiah
Canadian Prime Minister Clark MacDonald
Vizzini
George Bond
Baron Von Westphalen
Munk (voice)
Harold DeVoto
Self
Mugger
Freud
Waiter
Horatio Byrd
Masked Avenger
Mr. Gibson
Wally Shawn
Rex (voice) (uncredited)
Vanya
Mr. Gibbles (voice)
Mr. Wendell Hall
Principal Fetchit (voice)
Coleye
Sy
Sibor, Semage's Beau
John Lahr
Dr. Elliot Fibel
Booker / Broker / Lancealot Squarejaw
Mike Hoover
Oiseau
Birthday Party Guest (uncredited)
Sandy
Barnacle Paul (voice)
Colonel Wilson
Furnaceman
Gene
Principal Mazur (voice)
Henderson's Attorney
Earl
Dr. Fishbinder
Labrador MC (voice)
Otto Jaffe
Cashpot
Dr. Van Helsing
Cosmo
Doctor/Therapist
Ellen
Turtle
Gideon Rosen
Father Abruzzi
Clarence
Mr. Papadopoulos
Arthur Blake
Dr. Christian Burr (uncredited)
Jules Goldfarb
Rex (Voice)
Psychotherapist
Rex (voice) (archive footage)
Ezra
Halvard Solness
Assistant Insurance Man
Boss Man (voice)
Clinic Doctor
Eric Van Dongen
Simon Carr
Harry
Translator
Victor Finley
Kliegler
Marty
Mr. Willis
Workshop Member
Principal Crosby Strickler (voice)
Mr. Gelb
Gilbert Huph (voice)
Gary
Herman
Oliver
Professor Silverfish
Frank Judd
Calico (voice)
Howard
Mr. Woodley (voice)
Stan Spiegel
Everett Willits
Gary the Gadget Guy (voice)
Mr. Pardon
Billy (voice)
Principal Miller
David
Interviewer
Dr. Derek
Albert
Mr. Little
Izzie's Teacher
Mort Rifkin
Mr. Crocus
Frank
Broker / Booker / Lancelot Squarejaw
Math Teacher (uncredited)
Eustace Bagge
Tarzan Chimp (voice)
Echidna (voice)
Lucky
Mr. Mustela (voice)
Self (archive footage)
Larry
Bertram (voice)
Lonny Moon
Jeffrey Engels
Charles Haste
Howard Stiles
Dr. Von Oy
William Halsey
Film Professor
Arlos
Mr. Williams
William Badpastor
Humphrey (voice)
Cyrus Rose
Roy Batters
Charles Lester
Wallace Shawn (voice)
Warren Hughes
Arnie Ross
Rat King (voice)
Not-So-Magic-Mirror (voice)
Arnie
I.E. Shinn
Saul (voice)
Father Francis Ignatius
Zek
Jyle (voice)
Morris Mole (voice)
Barry (voice)
Pete (voice)
Evil Brain (voice)
Samuel
The Sorcerer
Benjamin Edelman
John Sturgis
(voice)
Wallace the Hernia (voice)
Martin Gable
Winslow Elliott
Kenneth Walters
Philip Ny (voice)
Dr. Warren Hughes
Mr. Neville
Tall (voice)