Ben Diskin
Nigel 'Numbuh 1' Uno / Hoagie Pennywhistle 'Numbuh 2' Gilligan Jr / Numbuh 101 (voice)
Lauren Tom
Kuki 'Numbuh 3' Sanban (voice)
Dee Bradley Baker
Wally 'Numbuh 4' Beatles / Mr. Fibb / Toilenator / Joaquin / Tommy Gilligan (voice)
Cree Summer
Abigail 'Numbuh 5' Lincoln / Former Numbuh 11 - Cree Lincoln (voice)
Jason Harris
Chad Dickson (voice)
Grey DeLisle
Crazy Old Cat Lady/Gramma Stuffum (voice)
Jeff Bennett
Mr. Boss / Mr. Fizz / Benedict Wigglestein (voice)
Jennifer Hale
Fanny 'Numbuh 86' Fulbright / Computer (voice)
Mark Hamill
Stickybeard (voice)
Tom Kenny
Knightbrace / Mr. Wink (voice)
Maurice LaMarche
Father (voice)
Matt Levin
Patton 'Numbuh 60' Drilovsky (voice)
Frank Welker
Monty Uno (voice)
Neil Ross
Grandfather (voice)
Daran Norris
Count Spankulot (voice)
Rachael MacFarlane
Rachael T. 'Numbuh 362' McKenzie (voice)
Ogie Banks
Sector Z Numbuh 0.1 - Bruce (voice)
Janice Kawaye
Sonya - Number 83 / Lee - Numbuh 84 (voice)
Dave Wittenberg
Numbuh Zero / Lenny - Sector Z Numbuh 0.4 (voice)
Cam Clarke
Additional Voices (voice)
Candi Milo
Additional Voices (voice)