Jim Carrey
Horton (voice)
Steve Carell
Mayor Ned McDodd (voice)
Carol Burnett
Kangaroo (voice)
Will Arnett
Vlad (voice)
Seth Rogen
Morton (voice)
Dan Fogler
Councilman / Yummo Wickersham (voice)
Isla Fisher
Dr. Mary Lou Larue (voice)
Jonah Hill
Tommy (voice)
Amy Poehler
Sally O'Malley (voice)
Jaime Pressly
Mrs. Quilligan (voice)
C
Charles Osgood
Narrator (voice)
Josh Flitter
Rudy (voice)
Niecy Nash
Miss Yelp (voice)
Jesse McCartney
JoJo (voice)
S
Shelby Adamowsky
Hedy / Hooly / Additional Voices (voice)
