Kathy Najimy

Kathy Lane

Matt Frewer

The Cat in the Hat

Christopher Lloyd

Mr. Hunch

Patrick Stewart

Sergeant Mulvaney

Billy Crystal

The Voice of America (voice)

Robin Williams

The Father

Howie Mandel

Sam-I-Am (voice)

Andrea Martin

The Ad Woman

David Paymer

The Ad Man

J.D. Daniels

Marco (segment "Mulberry Street")

Eileen Brennan

The Who-Villain

Graham Jarvis

The Farmer

Brady Bluhm

Marco (segment "McElligot's Pool")

Andraé Crouch

Yertle

Kevin Stea

Turtle Choir Member

Bambi Swayze

Turtle Choir Member

Zelda Williams

Daughter

Eleanor Columbus

Daughter

Kay E. Kuter

Dr. Seuss (voice)

Frank Welker

Additional Voice Overs (voice)

Malachi Pearson

Additional Voice Overs (voice)

Winston Churchill

Self - at Potsdam (archive footage) (uncredited)

Charles Durning

(voice) (uncredited)

June Foray

(voice) (archive footage) (uncredited)

Rudolf Heß

Self - with Hitler in Nuremberg (archive footage) (uncredited)

Adolf Hitler

Self (archive footage) (uncredited)

Bob Holt

(voice) (archive footage) (uncredited)

Boris Karloff

(voice) (archive footage) (uncredited)

Dr. Seuss

Self (archive footage)

Joseph Stalin

Self - at Potsdam (archive footage) (uncredited)

Julius Streicher

Self - with Hitler in Nuremberg (archive footage) (uncredited)

Paul Winchell

(voice) (archive footage) (uncredited)