 | Joey King als Ramona Quimby |
 | Selena Gomez als Beezus Quimby |
 | John Corbett als Robert Quimby |
 | Bridget Moynahan als Dorothy Quimby |
 | Ginnifer Goodwin als Aunt Bea |
 | Josh Duhamel als Hobart Kemp |
 | Sandra Oh als Mrs. Meacham |
 | Hutch Dano als Henry Huggins |
 | Sierra McCormick als Susan |
 | Jason Spevack als Howie Kemp |
 | Kathryn Zenna als Mrs. Kushner |
 | Janet Wright als Grandma Kemp |
 | Ruby Curtis als Willa Jean |
 | Patti Allan als Mrs. Pitt |
 | Garnet Harding als Mr. Swink |
 | Andrew McNee als Mr. Clay |
 | Tom Pickett als Mr. Cardoza |
 | Lynda Boyd als Mother (of Triplets) |
 | George C. Wolfe als Casting Director |
 | Nancy Robertson als Casting Associate |
 | Eileen Barrett als Minister |
 | Donnelly Rhodes als Crusty Photographer |
 | Brandi Alexander als Casting Wrangler |
 | Taylor Hickson als Girl In Cafeteria |
| Alison Greenspan | Producer |
| Laurie Craig | Screenplay |
| Nick Pustay | Screenplay |
| Beverly Cleary | Novel |
| Denise Di Novi | Producer |
| Elizabeth Allen Rosenbaum | Director |
| Brad Van Arragon | Co-Producer |
| John Bailey | Director of Photography |
| Brent Thomas | Production Design |
| Jane Moran | Editor |
| Carol Lavallee | Set Decoration |
| Shannon Grover | Art Direction |
| Patricia Hargreaves | Costume Design |
| Monica Huppert | Makeup Artist |
| Donna Bis | Hairstylist |
| Julia Michels | Music Supervisor |
| Christian Kaplan | Casting |
| Coreen Mayrs | Casting |
| Heike Brandstatter | Casting |
| J. Michael Williams | Unit Production Manager |
| Garvin Cross | Stunt Coordinator |
| Ryan Ennis | Stunt Coordinator |
| Ken Terry | Additional Editing |
| Martina Javorova | Set Designer |
| Adrien van Viersen | Storyboard |
| Iesza Jessica Jordan | Art Department Assistant |
| Madeleine Grant | Art Department Assistant |
| Jim Van Dijk | Camera Operator |
| Jim Van Dijk | Steadicam Operator |
| Karl Herrmann | Camera Operator |
| Alan Markfield | Still Photographer |
| Shane Connelly | Sound Mixer |
| Michael Hibberson | Boom Operator |
| Patti Henderson | Script Supervisor |
| John Morris | Supervising Sound Editor |
| Erik Aadahl | Sound Designer |
| Skip Lievsay | Sound Re-Recording Mixer |
| Gregg Landaker | Sound Re-Recording Mixer |
| Mike Moyer | Gaffer |
| Bill Dawson | Best Boy Electric |
| Sandra J. Blackie | Assistant Costume Designer |
| Keith A. Parent | Set Costumer |
| Neil Robertson | Location Manager |
| Susan Crawford | Production Coordinator |
| Rory Cutler | Special Effects Coordinator |
| Steven Michael Adams | Special Effects |
| Jesse Joslin | Construction Coordinator |
| Keith McCulloch | Construction Foreman |
| Lorraine Jamison | Unit Publicist |
| John Marquis | Sound Effects Editor |
| David V. Butler | Dialogue Editor |
| David Dowling | Property Master |
| Mark Mothersbaugh | Original Music Composer |
