Betty Thomas Director Zachary Levi Toby Actor David Cross Ian Actor Jason Lee Dave Actor 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 Wendie Malick Dr. Rubin Actor Anjelah Johnson-Reyes Julie Actor Kathryn Joosten Aunt Jackie Actor Kevin G. Schmidt Ryan Actor Chris Warren Jr. Xander Actor Bridgit Mendler Becca Actor Aimee Carrero Emily Actor Alexandra Shipp Valentina Actor Gregg Binkley Emcee Actor Jon Vitti Screenwriter Jonathan Aibel Screenwriter Glenn Berger Screenwriter Janice Karman Producer Karen Rosenfelt Executive Producer Arnon Milchan Executive Producer Michele Imperato Executive Producer Steve Waterman Executive Producer Anthony B. Richmond Cinematographer Marcia Hinds Production Design Matt Friedman Film Editing David Newman Original Music Alexandra Welker Costume Design Juel Bestrop Casting Seth Yanklewitz Casting Bo Johnson Art Director Karen Agresti Set Decoration