 | Eddie Murphy | | Dr. John Dolittle |
| Kristen Wilson | | Lisa Dolittle |
| Raven-Symoné | | Charisse Dolittle |
| Kyla Pratt | | Maya Dolittle |
| Lil' Zane | | Eric |
| Denise Dowse | | Secretary |
| James Avery | | Eldon (as James L. Avery) |
| Elayn J. Taylor | | Eldon's Wife |
| Andy Richter | | Eugene Wilson |
| Kevin Pollak | | Riley / Alligator |
| Victor Raider-Wexler | | Judge B. Duff |
| Jeffrey Jones | | Joe Potter |
| Mark Griffin | | Logger / Nature Show Narrator |
| Ken Hudson Campbell | | Animal Control Officer / Dog / Animal Groupie #3 / Forest Animal (voice) (as Ken Campbell) |
| Anne Stedman | | Woman |
| Tommy Bush | | Farmer |
| Adam Vernier | | Farm Worker |
| Chris Marley | | Yuppie Man |
| Shaun Robinson | | Newscaster |
| Googy Gress | | Bear Announcer |
| Lisa Marie Hugueley | | Shamu Trainer (as Lisa Hugueley) |
| Steve Irwin | | The Crocodile Hunter |
| Doug Seus | | Klondike Dave Delivery Man (as R. Doug Seus) |
| Louise Osbourne | | Waitress (as Louise Lennon) |
| Brie Hill Arbaugh | | Chihuahua Lady |
| E.J. Wessel | | Guy Throwing Frisbee |
| Steve Zahn | | Archie (voice) |
| Lisa Kudrow | | Ava (voice) |
| Jacob Vargas | | Pepito (voice) |
| Michael Rapaport | | Joey the Raccoon (voice) |
| Isaac Hayes | | Possum (voice) |
| Andy Dick | | Lennie the Weasel (voice) |
| Joey Lauren Adams | | Squirrel (voice) |
| Maria Arcé | | Fish (voice) |
| Melique Berger | | Fish (voice) (as Melique T. Berger) |
| David Cross | | Dog / Animal Groupie #2 (voice) |
| David DeLuise | | School Fish #2 (voice) |
| Trevor Denman | | Horse Race Announcer (voice) |
| John DiMaggio | | Seeing Eye Dog / Wassup Fish / Mouse (voice) |
| Georgia Engel | | Giraffe (voice) |
