On screen
Cast
26 credited performers
Richard Steven Horvitz
Zim (voice)
Andy Berman
Dib (voice)
Rosearik Rikki Simons
GIR (voice)
Melissa Fahn
Gaz (voice)
Lucille Bliss
Ms. Bitters (voice)
Rodger Bumpass
Professor Membrane (voice)
Kevin McDonald
Almighty Tallest Purple (voice)
Wally Wingert
Character not listed
Mo Collins
Character not listed
Danny Cooksey
Character not listed
Olivia D'Abo
Character not listed
Candi Milo
Girl (voice)
Jhonen Vasquez
Computer Voice / Old Kid / Brian (voice)
R. Lee Ermey
Character not listed
Eliza Schneider
Character not listed
S. Scott Bullock
Character not listed
Sherman Howard
Oog-Oh (voice)
Dwight Schultz
Character not listed
Greg Ellis
Character not listed
Philece Sampler
Scientist #4 / Germ Woman / Tiny Germ Voice (voice)
Dee Bradley Baker
Santa Gerg / Guy in Crowd #1 / Cutest Little Kid (voice)
Kathryn Fiore
Kid / Santa Fan #2 / Little Girl (voice)
Jeffrey Jones
Presidentman / Crowd Man / Guy in Crowd #2 (voice)
Brad Abrell
Announcer (voice)
Phil LaMarr
The Letter M (voice)
Michael McDonald
RoboDad / Crewman (voice)