James 'Jimmy' Isaac Neutron (voice)
Judy Neutron / VOX (voice)
Hugh Neutron / Pilot / Arena Guard (voice)
Sheen Estevez (voice)
King Goobot V (voice)
Ooblar (voice)
Goddard / Poultra (voice)
Carl Wheezer / Mr. and Mrs. Wheezer / Kid in Classroom (voice)
Cindy Vortex (voice)
Libby Folfax (voice)
Nick Dean / Britney / PJ (voice)
Yokian Guard / Gus (voice)
Mr. Estevez (voice)
Ultra Lord / Mission Control / General Bob (voice)
Bobby / Kid / Control Yokian (voice)
Zachary / Reporter / Angie / Libby's Mom (voice)
Ms. Winfred Fowl (voice)
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)
Yokian Newscaster #2 (voice)
Yokian Newscaster #1 (voice)
Norad Officer (voice)
Hostess (voice)
Octapuke Kid / Guard / Bennie (voice)
Guard (voice)
Yokian Incubator Operator (voice)
Little Girl / Camera Person (voice)
Chris (voice)
Digital Voice (voice)
Screamer (voice)
Screamer (voice)
Hyperactive Kid / Arena Yokian (voice)