 | Freddie Highmore als Jared Grace / Simon Grace |
 | Sarah Bolger als Mallory Grace |
 | David Strathairn als Arthur Spiderwick |
 | Mary-Louise Parker als Helen Grace |
 | Nick Nolte als Mulgarath |
 | Joan Plowright als Aunt Lucinda Spiderwick |
 | Andrew McCarthy als Richard Grace |
 | Seth Rogen als Hogsqueal (voice) |
 | Martin Short als Thimbletack (voice) |
 | Jordy Benattar als Young Lucinda Spiderwick |
 | Lise Durocher-Viens als Mrs. Spiderwick |
 | Tod Fennell als Helen's Co-Worker |
 | Mariah Inger als Nurse |
| Jeremy Lavalley als Tow Truck Driver |
| Kyle Switzer als Additional Performer |
 | Tyler Patrick Jones als Additional Performer |
 | Ron Perlman als Red Cap (voice) (uncredited) |
| Caleb Deschanel | Director of Photography |
| James Horner | Original Music Composer |
| Tony DiTerlizzi | Novel |
| Karey Kirkpatrick | Producer |
| Karey Kirkpatrick | Screenplay |
| Holly Black | Novel |
| John Sayles | Screenplay |
| Mark Waters | Director |
| David Berenbaum | Screenplay |
| Jim Kontos | Unit Manager |
| Sarah Broshar | Assistant Editor |
| James D. Bissell | Production Design |
| Marci Liroff | Casting |
| Réjean Goderre | Key Hair Stylist |
| Joanna Johnston | Costume Design |
| Kimi Webber | Script Supervisor |
| Michael Kahn | Editor |
| Annick Chartier | Makeup Department Head |
| Cheryl A. Tkach | Associate Producer |
| Robert Parle | Art Direction |
| Martine Giguère-Kazemirchuk | Set Decoration |
| Alex Touikan | Set Designer |
| Michael Lantieri | Special Effects Supervisor |
| Ellen Goldsmith-Vein | Producer |
| Alison Parraco | Visual Effects Coordinator |
| Mark Burgeois | Additional Editing |
| David Gaucher | Art Direction |
| Christa Munro | Art Direction |
| Brent Lambert | Set Designer |
| Odette Gadoury | Costume Design |
| Martin Gagné | Set Designer |
| Mark de Coste | Assistant Costume Designer |
| James Sanchez | Transportation Captain |
| David McKeown | Stunt Coordinator |
| Josette Perrotta | Co-Producer |
| Pablo Helman | Visual Effects Supervisor |
| Joey Box | Stunt Coordinator |
| Carole Theriault | Art Department Coordinator |
| Marie-Elaine Bailly | Production Coordinator |
| Brooks Baldwin | Dialect Coach |
| Jim Henrikson | Music Editor |
| Tom C. Peitzman | Co-Producer |
| Isabelle Guay | Supervising Art Director |
| Céline Lampron | Set Designer |
| Louis Piché | Boom Operator |
| Sean Samuels | Storyboard |
| Takashi Seida | Still Photographer |
| Steven Woloshen | Transportation Co-Captain |
| Patrick Crane | First Assistant Editor |
| Mark A. Mangini | Sound Designer |
| Piero Mura | Sound Effects Editor |
| Julie Kane-Ritsch | Co-Producer |
| Joe Sanchez | Transportation Coordinator |
| Christopher Raimo | Visual Effects Producer |
| Silenn Thomas | Associate Producer |
| Louis Craig | Special Effects Supervisor |
| Robin D. Cook | Casting |
| Helene Lamarre | Art Department Coordinator |
| Daniel Hamelin | Set Decoration |
| Anna Behlmer | Sound Re-Recording Mixer |
| Tony DiTerlizzi | Executive Producer |
| Frédéric Amblard | Set Designer |
| Francois Archambault | Steadicam Operator |
| Mark Binder | Special Sound Effects |
| Dick Bernstein | Music Editor |
| Jean-Pierre Paquet | Art Direction |
| Josette Perrotta | Production Manager |
| Robert Stecko | Camera Operator |
| Philippe Lord | Set Decoration |
| Louis Marion | Sound Mixer |
| Michèle St-Arnaud | Location Manager |
| David Whitehead | Special Sound Effects |
| Mark Canton | Producer |
| Steve Blalock | Stunt Coordinator |
| Holly Black | Executive Producer |
| Tim Alexander | Visual Effects Supervisor |
| Mario Chabot | Set Designer |
| Simon Guilbault | Set Designer |
| Maryse de Lottinville | Set Designer |
| Francois Archambault | Camera Operator |
| Chantal Bergeron | Hairstylist |
| Alan Howarth | Special Sound Effects |
| Kevin Yagher | Makeup Effects |
| Peter J. Silbermann | Unit Publicist |
| Ben Rosenblatt | Post Production Supervisor |
| Andy Nelson | Sound Re-Recording Mixer |
| Jim Passon | Color Timer |
| Larry J. Franco | Producer |
| Julia Pistor | Executive Producer |
| Lucie Tremblay | Set Designer |
| Martin Allan Kloner | Visual Effects Editor |
| Geralyn Flood | Casting Associate |
| Phil Tippett | Animation Supervisor |
| Christopher T. Welch | Supervising Dialogue Editor |
| Avram D. Gold | Dialogue Editor |
| Ralph Osborn | Dialogue Editor |
| Julie Feiner | Dialogue Editor |
| Val Kuklowsky | Dialogue Editor |
| Christopher T. Welch | Supervising ADR Editor |
| Mickael Coedel | Animation |
| Francis Back | Storyboard Artist |
| Katina Waters | Stunts |
| France Raymond | Stunts |
| Gilbert Larose Jr. | Stunts |
| Nathalie Girard | Stunts |
| Nicole Germain | Stunts |
| Pascal Archambault Bouffard | Stunts |
| Joe Bailey | Compositor |
| Daniel Bryant | Compositor |
| Chris Gibbons | Compositor |
| Chris Halstead | Compositor |
| David A. Link | Compositor |
| Tom Rosseter | Compositor |
| Russ Sueyoshi | Compositor |
| Natalie Baillie | Compositor |
| Shelley Campbell | Compositor |
| Charles Granich | Compositor |
| Steve Jaworski | Compositor |
| Kristen Millette | Compositor |
| Jordan Schilling | Compositor |
| Alan Boucek | Compositor |
| Michael Clemens | Compositor |
| Scott Hale | Compositor |
| Michael Kennen | Compositor |
| Satish Ratakonda | Compositor |
| David Schnee | Compositor |
| Mark Tamny | Compositor |
| Colin Epstein | Compositing Supervisor |
| Carlos Huante | Character Designer |
| Brian Kalin O'Connell | Character Designer |
| Steve Rawlins | Lead Animator |
| John Zdankiewicz | Lead Animator |
| Robert Bowen | Painter |
| Alexis Robert | Painter |
| Philippe Duberger | Painter |
| Hélène Tessier | Painter |
| Annie St-Pierre | Painter |
| Jacques Viennet | Painter |
| Rejean Brochu | Head Carpenter |
| Alain Brochu | Head Carpenter |
| Mark Coffey | Assistant Sound Editor |
| Rodrigo Ortiz-Parraga | Assistant Sound Editor |
| Andy Sisul | First Assistant Sound Editor |
| Denis Verrette | Production Assistant |
| Marianne Germain | Production Assistant |
| Mathieu Gosselin | Production Assistant |
| Simon Asselin | Production Assistant |
| Eva Quintero | Production Assistant |
| Jocelyne Allard | Production Assistant |
| Marco Légaré | Production Assistant |
| Spiro Tsovras | Production Assistant |
| Dominique Gaglione D'Amico | Production Assistant |
| Maxime Langlois | Production Assistant |
| Marc Tessier | Production Assistant |
| Patrick Chevrier | Production Assistant |
| Fred Berger | Production Assistant |
| Tommy Guenette | Production Assistant |
| Lyssa J. Caster | Production Accountant |
| Dominic Gerard | Production Assistant |
| Yvan Francouer | Production Assistant |
| Josianne Mailloux | Production Secretary |
| Sean Samuels | Storyboard Artist |
| Adrien Morot | Special Effects Makeup Artist |
| Bruno Gatien | Special Effects Makeup Artist |
| Caroline Aquin | Special Effects Makeup Artist |
| Marie-France Guy | Special Effects Makeup Artist |
| Steve Barnett | Co-Producer |
| Shawn Kelly | Animation |
