Ewan McGregor as Rodney Copperbottom (voice)

Robin Williams as Fender (voice)

Halle Berry as Cappy (voice)

Amanda Bynes as Piper (voice)

Mel Brooks as Bigweld (voice)

Jim Broadbent as Madame Gasket (voice)

Greg Kinnear as Ratchet (voice)

Stanley Tucci as Herb Copperbottom (voice)

Dianne Wiest as Mrs. Copperbottom (voice)

Drew Carey as Crank (voice)

Harland Williams as Lug (voice)

Jennifer Coolidge as Aunt Fanny (voice)

Paul Giamatti as Tim the Gate Guard (voice)

Natasha Lyonne as Loretta Geargrinder (voice)

Chris Wedge as Wonderbot / Phone Booth (voice)

Dan Hedaya as Mr. Gunk (voice)

Marshall Efron as Lamppost / Toilet Bot / Bass Drum / Microphone

Terry Bradshaw as Broken Arm Bot (voice)

Al Roker as Mailbox (voice)

Lucille Bliss as Pigeon Lady (voice)

Jay Leno as Fire Hydrant (voice)

Lowell Ganz as Mr. Gasket (voice)

Paula Abdul as Watch (voice)

Jackie Hoffman as Water Cooler (voice)

Brian Scott McFadden as Trashcan Bot (voice)

Tim Nordquist as Tin Man (voice)

James Earl Jones as Voice Box at Hardware Store (voice)

Damien Fahey as Stage Announcer (voice)

Stephen Tobolowsky as Bigmouth Executive / Forge (voice)

Jansen Panettiere as Younger Rodney (voice)

Will Denton as Young Rodney (voice)

Crawford Wilson as Young Rodney (voice)

Dylan Denton as Youngest Rodney (voice)

Jennifer Perito as Additional Voices

Alan Rosenberg as Jack Hammer (voice)

Lara Cody as Additional Voices

Cooper Cowgill as Additional Voices

David Crommett as Additional Voices

Darin De Paul as Additional Voices

Dann Fink as Additional Voices

Timothy Gulan as Additional Voices

Ray Iannicelli as Additional Voices

Sondra James as Additional Voices

Vanessa Lemonides as Additional Voices

Marcus Maurice as Additional Voices

David Rossmer as Additional Voices

Bruce Winant as Additional Voices / ADR Loop Group

Chris Moyles as Stage Announcer (voice)

Chingy as DJ Robot (uncredited)

Sean Garnhart as Diesel (uncredited)

Paul Urmson as Diesel (uncredited)

Randy Jackson as Watch #2 (voice) (uncredited)

James Brown as Diesel (archive footage) (uncredited)