Jason Lee

Dave

David Cross

Ian

Jenny Slate

Zoe

Justin Long

Alvin (voice)

Matthew Gray Gubler

Simon (voice)

Jesse McCartney

Theodore (voice)

Amy Poehler

Eleanor (voice)

Anna Faris

Jeanette (voice)

Christina Applegate

Brittany (voice)

Alan Tudyk

Simone (voice)

Michael P. Northey

Hawaiian Shirt Guy

Lauren Gottlieb

Club Woman #2

Andy Buckley

Captain Correlli

Chad Krowchuk

Waiter

Luisa d'Oliveira

Tessa

Tucker Albrizzi

Tucker / Kite Kid

Nelson Wong

Casino Guy

Ian Harmon

Monster

Phyllis Smith

Flight Attendant

Ross Bagdasarian, Jr.

Alvin (singing voice) (uncredited)

Janice Karman

Theodore / The Chipettes (singing voice) (uncredited)

Jeremy Palko

Cruise Guy (uncredited)