Frank Welker
Goddard (voice) / Poultra (voice)
Rob Paulsen
Carl Wheezer (voice) / Mr. Wheezer (voice) / Mrs. Wheezer (voice) / Kid in Classroom (voice)
Carolyn Lawrence
Cindy Vortex (voice)
Crystal Scales
Libby Folfax (voice)
Candi Milo
Nick Dean (voice) / Britney (voice) / PJ (voice)
David L. Lander
Yokian Guard (voice) / Gus (voice)
Carlos Alazraqui
Mr. Estevez (voice)
Jim Cummings
Ultra Lord (voice) / Mission Control (voice) / General Bob (voice)
Keith Alcorn
Bobby (voice) / Kid (voice) / Control Yokian (voice)
Kimberly Brooks
Zachary (voice) / Reporter (voice) / Angie (voice) / Libby's Mom (voice)
Andrea Martin
Ms. Winfred Fowl (voice)
Billy West
Bobby's Twin Brother (voice) / Butch (voice) / Jailbreak Cop (voice) / Old Man Johnson (voice) / Robobarber (voice) / Flurp Announcer (voice) / Yokian Officer (voice) / Anchor Boy (voice) / Guard (voice)
Bob Goen
Yokian Newscaster #1
Mary Hart
Yokian Newscaster #2 (voice)
Bob Goen
Yokian Newscaster #1 (voice)
Dee Bradley Baker
Norad Officer (voice)
Greg Eagles
Libby's Dad (voice)
Jack Angel
Additional Voices (voice)
Laraine Newman
Hostess (voice)
Gregg Berger
Additional Voices (voice)
Mickie McGowan
Additional Voices (voice)
Phil Proctor
Additional Voices (voice)