Debi Derryberry

as Jimmy Neutron / Alien Actress / Alien Woman (voice)

Rob Paulsen

as Carl Wheezer/Mr. Wheezer/Mrs. Wheezer/Test Pilot/Announcer (voice)

Jeffrey Garcia

as Sheen Estevez / Army Guard (voice)

Frank Welker

as Goddard (voice)

Carolyn Lawrence

as Cindy Vortex (voice)

Crystal Scales

as Libby Folfax (voice)

Tim Allen

as Meldar Prime (voice)

Alyssa Milano

as April (voice)

Carlos Alazraqui

as Sr. Estevez (voice)

Jeff Bennett

as Gorlock #2 / Brain #1 (voice)

Megan Cavanagh

as Judy Neutron / Mrs. Vortex (voice)

Jim Cummings

as Brain #2 / Mayor Quadar (voice)

Mark DeCarlo

as Hugh Neutron / Emergency System / Gen. Abercrombie (voice)

Jess Harnell

as Meldar Prime (singing voice)

Joe Lala

as Sr. Estevez (voice)

Phil LaMarr

as Bolbi Stroganofsky / British Tourist (voice)

Billy West

as Sam / Corky Shumatsu (voice)

Grey DeLisle

as Vendanna (voice)