Zachary Levi as Toby

David Cross as Ian

Jason Lee as Dave

Justin Long as Alvin (voice)

Matthew Gray Gubler as Simon (voice)

Jesse McCartney as Theodore (voice)

Amy Poehler as Eleanor (voice)

Anna Faris as Jeanette (voice)

Christina Applegate as Brittany (voice)

Wendie Malick as Dr. Rubin

Anjelah Johnson-Reyes as Julie

Kathryn Joosten as Aunt Jackie

Kevin G. Schmidt as Ryan

Chris Warren as Xander

Bridgit Mendler as Becca

Aimee Carrero as Emily

Alexandra Shipp as Valentina

Gregg Binkley as Emcee

Jake Zyrus as Charice Pempengco

Bernard White as Doctor

Adele Jacques as Nurse

Joy Osmanski as Airline Rep

Archie Hahn as Agent

Lanny Joon as Paramedic

Brando Eaton as Jeremy

Michael Bruno as Honor Society

Andrew Lee Schmidt as Honor Society

Alexander Noyes as Honor Society

Jason Rosen as Honor Society

Ali Mikles as Screaming Fan

Eric Bauza as Digger the NASCAR Gopher (voice)

Sean Astin as Meerkat Manor Narrator (voice)

Marty Dew as Chipmunk Dancer

Richy Jackson as Chipmunk Dancer

Mihran Kirakosian as Chipmunk Dancer

Janelle Ginestra as Chipette Dancer

Thomasina Gross as Chipette Dancer

Rachele Brooke Smith as Chipette Dancer

Ryan Conferido as Li'l Rosero Dancer

Hokuto 'Hok' Konishi as Li'l Rosero Dancer

Ryan Feng as Li'l Rosero Dancer

D-Trix as Li'l Rosero Dancer

Brian Hirano as Li'l Rosero Dancer

Steve Terada as Li'l Rosero Dancer

Victor Kim as Li'l Rosero Dancer

Brittany Anne Pirtle as Cheerleader (uncredited)

Ross Bagdasarian, Jr. as Alvin (singing voice) (uncredited)

Janice Karman as Theodore / The Chipettes (singing voice) (uncredited)

Courtney Platt as Eleanor - Performer (voice) (uncredited)

Gee Alexander as Simon Dance Double (uncredited)

Mark Alkofer as Football Referee (uncredited)

Tallie Brinson as Principal Dancer (uncredited)

Ericka Clevenger as Cheerleader (uncredited)

Sean Decker as Dodgeball Player (uncredited)

Sarah Fontenot as Cheerleader (uncredited)

Paul Gonzales as Charice Bassist (uncredited)

David Lautman as High School Student (uncredited)

Casper Smart as Dancer (uncredited)

Andrew 'Drew' Thompson as Stadium Announcer (uncredited)