Debi Derryberry

James 'Jimmy' Isaac Neutron (voice)

Tibor Lubinszky

Megan Cavanagh

Judy Neutron (voice) / VOX (voice)

Gyula Szöreghy

Mark DeCarlo

Hugh Neutron (voice)

Lili Berky

Jeffrey Garcia

Sheen Estevez (voice)

Ödön Bàrdy

Patrick Stewart

King Goobot V (voice)

Gyula Dezséri

Martin Short

Ooblar (voice)

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)