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)