Ben Stiller as Toby Katzenberg, Stacy's husband and Colby and Felicia's father in the film
Drew Barrymore as Stacy Katzenberg, Toby's wife and Colby and Felicia's mother in the film)
Owen Vaccaro as Colby Katzenberg, Felicia's brother and Toby and Stacy's son in the film
Scarlett Estevez as Felicia Katzenberg, Colby's sister and Toby and Stacy's daughter in the film)
Buster Bunny (voiced by John Kassir, succeeding from Charles Adler respectively)
George Bunny (also voiced by John Kassir respectively)
Babs Bunny (voiced by Tress MacNeille respectively)
Witch Hazel (also voiced by Tress MacNeille, succeeding from the late June Foray respectively)
Dot Warner, cameo appearance (also voiced by Tress MacNeille respectively)
Hello Nurse, cameo appearance (also voiced by Tress MacNeille respectively)
Mona Bunny (also voiced by Tress MacNeille respectively)
Maria Duck (also voiced by Tress MacNeille respectively)
Professor Penelope (also voiced by Tress MacNeille respectively)
Bubbie Pig (also voiced by Tress MacNeille respectively)
Librarian Prissy (also voiced by Tress MacNeille respectively)
Minerva Mink (voiced by Julie Brown respectively)
Brian Beaver (voiced by Charles Adler, ever since Ickis's voice on AAAAAAH! Real Monsters)
Plucky Duck (voiced by Jason Marsden, sounding like a mix between Daffy Duck from the Looney Tunes franchise and Danger Duck from Loonatics Unleashed, succeeding from the late Joe Alaskey respectively)
Hamton Pig (voiced by Billy West, succeeding from the late Don Messick respectively)
Professor Elmer (also voiced by Billy West, succeeding from the late Arthur Q. Bryan and the late Joe Alaskey respectively)
Shirley the Loon (voiced by Gail Matthius respectively)
Fifi La Fume (voiced by Kath Soucie respectively)
Professor Lola (also voiced by Kath Soucie respectively)
Li'l Sneezer (also voiced by Kath Soucie respectively)
Montana Max (voiced by Danny Cooksey respectively)
Elmyra Duff (voiced by Cree Summer Francks respectively)
Mary Melody (also voiced by Cree Summer Francks respectively)
Professor Bugs (voiced by Jeff Bergman, succeeding from the late Mel Blanc, the late Greg Burson and the late Joe Alaskey respectively)
Professor Sylvester (also voiced by Jeff Bergman, succeeding from the late Mel Blanc, the late Greg Burson and the late Joe Alaskey respectively)
Professor Tweety (also voiced by Jeff Bergman, succeeding from the late Mel Blanc, the late Greg Burson and the late Joe Alaskey respectively)
Professor Wile E. (voiced by John Paul Karliak, succeeding from the late Mel Blanc, the late Greg Burson and the late Joe Alaskey respectively)
Sweetie Bird (voiced by Candi Milo respectively)
Granny (also voiced by Candi Milo, succeeding from the late June Foray respectively)
Fowlmouth (voiced by Rob Paulsen respectively)
Yakko Warner, cameo appearance (also voiced by Rob Paulsen respectively)
Concord Condor (also voiced by Rob Paulsen respectively)
Arnold the Pit Bull (also voiced by Rob Paulsen respectively)
Betsy Bunny (voiced by Jennifer Hale, ever since Billy's mother, Gladys's voice on The Grim Adventures of Billy and Mandy)
Wakko Warner (voiced by Jess Harnell respectively)
Slappy Squirrel (voiced by Sherri Stoner respectively)
Skippy Squirrel (voiced by Connor Corum, his own voice)
Furrball (voiced by Frank Welker respectively)
Chicken Boo (also voiced by Frank Welker respectively, chicken sound effects)
Byron Bassett (also voiced by Frank Welker respectively, puppy dog sound effects)
Barky Marky (also voiced by Frank Welker respectively, puppy dog sound effects)
Calamity Coyote (also voiced by Frank Welker Respectively)
Gogo Dodo (also voiced by Frank Welker respectively)
Little Beeper (also voiced by Frank Welker respectively, beep-beep sound effects)
Uncle Stinky (also voiced by Frank Welker respectively, pig grunting sound effects)
Professor Road Runner (also voiced by Frank Welker, beep-beep sound effects, succeeding from the late Mel Blanc, the late Greg Burson and the late Joe Alaskey respectively)
Dizzy Devil (voiced by Maurice LaMarche respectively)
Coach Sam (also voiced by Maurice LaMarche, succeeding from the late Mel Blanc, the late Greg Burson and the late Joe Alaskey respectively)
Principal Taz (voiced by Jim Cummings respectively)
Wade Pig (also voiced by Jim Cummings, succeeding from both the late Jonathan Winters and the late Joe Alaskey respectively)
Sappy Stanley (also voiced by Jim Cummings, succeeding from the late Jonathan Winters respectively)
Pappy Pig (also voiced by Jim Cummings respectively)
Winnie Pig (voiced by Edie McClurg respectively)
Dr. Splicer (voiced by Jeff Altman respectively)
Master X (voiced by Corey Burton, evil sounding voice)