Debi Derryberry as Jimmy Neutron (voice)

Tara Strong as Timmy / School Girl (voice)

Rob Paulsen as Carl / Anti-Fairy Walla (voice)

Jeffrey Garcia as Sheen / Anti-Fairy Walla (voice)

Carolyn Lawrence as Cindy Vortex (voice)

Crystal Scales as Libby Folfax (voice)

Frank Welker as Goddard (voice)

Susanne Blakeslee as Wanda / Mom / Anti-Wanda / Anti-Fairy #1 (voice)

Daran Norris as Cosmo / Dad / Jorgen Von Strangle / Anti-Cosmo (voice)

Carlos Alazraqui as Mr. Crocker (voice)

Dee Bradley Baker as Binky (voice)

Gary LeRoi Gray as A.J. (voice)

Jim Ward as Chet Ubetcha / Anti-Fairy #2 (voice)

Jeff Bennett as Dr. Moist (voice)

Kevin Michael Richardson as Morgan Freeman / Anti-Fairy Walla (voice)

Tim Curry as Professor Calamitous (voice)

Grey DeLisle as Vicky (voice)