Alfred Molina (68)

Professor Knight (voice)

Ferrell Barron

Additional Monsters (voice)

Aisha Tyler (50)

Millie (voice)

Bob Uecker (86)

Bob Yucker (voice)

Dave Wittenberg (49)

Fan Monster (voice) / Additional Monsters (voice)

John Michael Higgins (58)

Argus Blinks (voice)

Michaela Dietz (38)

Additional Monsters (voice) / Snore (voice)

Bob Peterson (60)

Roze (voice) / Roz (voice) / Roz / Roze (voice) / Roze / Bob Peterson (voice) / Roz / Bob Peterson (voice)

Bobs Gannaway (56)

Roto (voice) / Otis / Roto / Bobs (voice) / Roto / Otis (voice) / Otis / Chalooby (voice)

Hadley Gannaway (13)

Thalia (voice)

Devin Bright

Marcus (voice)

Cooper J. Friedman (12)

Alexander (voice)

Lucian Perez

Oscar (voice)

Isabella Abiera (11)

Gurty (voice)

Gabriel Iglesias (44)

Gary (voice)

Jennifer Tilly (62)

Celia Mae (voice)

John Ratzenberger (74)

Bernard (voice) / Adorable (voice) / Yeti (voice) / Bernard / Arodable (voice) / Adorable / Bernard (voice)

Bonnie Hunt (59)

Ms. Flint (voice)

Curtis Armstrong (67)

Mr. Crummyham (voice)

Stephen Stanton (59)

Smitty / Needleman / Sanderson (voice) / Smitty / Needleman (voice) / Sanderson (voice) / Smitty / Needleman / Chuck (voice) / Smitty / Needleman / Sanderson / Reporter 2 (voice) / Sanderson / Chuck (voice) / Smitty / Needleman / Sanderson / Chuck (voice)

Nathan Fillion (50)

Johnny (voice)

Jenifer Lewis (64)

Grandma Tuskmon (voice)

Ali Wong (39)

Jill (voice)

Joe Lo Truglio (50)

Jack (voice)

Christopher Swindle (49)

Phlegm (voice) / Fungus (voice) / Bathroom Monsters / Four-Eyed Monster / McLean (voice) / Restaurant Patrons / Sidewalk Monster (voice) / Phlegm / Rudy / Additional Monsters (voice) / Fungus / Ted / Phlegm (voice) / M.E.R.C. Official 2 / Phlegm / Additional Monsters (voice) / Fungus / Phlegm / McLean / Additional Monsters (voice) / Fungus / Don / Charlie (voice) / Phlegm / Fungus / Ted / Little Boy (voice) / Phlegm / Fungus (voice) / Additional Monsters (voice) / Fungus / Phlegm / Charlie (voice) / Phlegm

Alan Kim (9)

Ben (voice)

Aubrey Plaza (37)

Claire (voice)

Julia Butters (12)

Lorelei (voice)

Sander Argabrite

J.J. (voice)

Carlos Alazraqui (58)

Restaurant Patrons (voice) / Josh Rivera / Jebediah (voice) / John Rivera (voice) / Business Monster (voice) / Additional Monsters (voice) / David / Josh Rivera (voice) / Rudy the Service Monster (voice)