Matthew Gray Gubler
Simon (voice)
Jesse McCartney
Theodore (voice)
Amy Poehler
Eleanor (voice)
Anna Faris
Jeanette (voice)
Christina Applegate
Brittany (voice)
Anjelah Johnson-Reyes
Julie
Kathryn Joosten
Aunt Jackie
Jake Zyrus
Charice Pempengco
Michael Bruno
Honor Society
Andrew Lee Schmidt
Honor Society
Alexander Noyes
Honor Society
Eric Bauza
Digger the NASCAR Gopher (voice)
Sean Astin
Meerkat Manor Narrator (voice)
Richy Jackson
Chipmunk Dancer
Mihran Kirakosian
Chipmunk Dancer
Janelle Ginestra
Chipette Dancer
Thomasina Gross
Chipette Dancer
Rachele Brooke Smith
Chipette Dancer
Ryan Conferido
Li'l Rosero Dancer
Hokuto 'Hok' Konishi
Li'l Rosero Dancer
Ryan Feng
Li'l Rosero Dancer
Brian Hirano
Li'l Rosero Dancer
Steve Terada
Li'l Rosero Dancer
Victor Kim
Li'l Rosero Dancer
Brittany Anne Pirtle
Cheerleader (uncredited)
Ross Bagdasarian, Jr.
Alvin (singing voice) (uncredited)
Janice Karman
Theodore / The Chipettes (singing voice) (uncredited)
Courtney Platt
Eleanor - Performer (voice) (uncredited)
Gee Alexander
Simon Dance Double (uncredited)
Mark Alkofer
Football Referee (uncredited)
Tallie Brinson
Principal Dancer (uncredited)
Ericka Clevenger
Cheerleader (uncredited)
Sean Decker
Dodgeball Player (uncredited)
Sarah Fontenot
Cheerleader (uncredited)
Paul Gonzales
Charice Bassist (uncredited)
David Lautman
High School Student (uncredited)
Casper Smart
Dancer (uncredited)
Andrew 'Drew' Thompson
Stadium Announcer (uncredited)