 | Jessica Chastain als Beverly Marsh |
 | James McAvoy als Bill Denbrough |
 | Bill Hader als Richie Tozier |
 | Isaiah Mustafa als Mike Hanlon |
 | Jay Ryan als Ben Hanscom |
 | James Ransone als Eddie Kaspbrak |
 | Andy Bean als Stanley Uris |
 | Bill Skarsgård als Pennywise |
 | Jaeden Martell als Young Bill Denbrough |
 | Wyatt Oleff als Young Stanley Uris |
 | Jack Dylan Grazer als Young Eddie Kaspbrak |
 | Finn Wolfhard als Young Richie Tozier |
 | Sophia Lillis als Young Beverly Marsh |
 | Chosen Jacobs als Young Mike Hanlon |
 | Jeremy Ray Taylor als Young Ben Hanscom |
 | Teach Grant als Henry Bowers |
 | Nicholas Hamilton als Young Henry Bowers |
 | Javier Botet als Hobo / The Witch |
 | Xavier Dolan als Adrian Mellon |
 | Taylor Frey als Don Hagarty |
 | Molly Atkinson als Myra / Sonia Kaspbrak |
 | Joan Gregson als Mrs. Kersh |
 | Stephen Bogaert als Alvin Marsh |
 | Luke Roessler als Dean |
 | Stephen King als Shopkeeper |
 | Peter Bogdanovich als Peter |
 | Will Beinbrink als Tom |
 | Jess Weixler als Audra Phillips |
 | Martha Girvin als Patty |
 | Ryan Kiera Armstrong als Victoria Fuller |
 | Jackson Robert Scott als Dead Georgie |
 | Jake Weary als Webby |
 | Katie Lunman als Chris Unwin |
 | Kelly Van der Burg als Victoria's Mom |
 | Jason Fuchs als Richie's Manager |
 | Joe Bostick als Mr. Keene |
 | Megan Charpentier als Young Gretta |
 | Juno Rinaldi als Gretta |
 | Neil Crone als Chief Borton |
 | Ry Prior als Connor |
 | Owen Teague als Dead Hocksstetter |
 | Jake Sim als Belch Huggins |
 | Logan Thompson als Victor Criss |
 | Connor Smith als Carny |
 | Amanda Zhou als Waitress |
 | Rob Ramsay als Meaner Nurse |
 | John Connon als John Koontz (Juniper Hill Security) |
 | Doug MacLeod als Head Honcho |
 | Brandon Crane als Big Guy |
 | Erik Junnola als Scuzzah |
 | Josh Madryga als Scuzzah |
 | Peter George Commanda als Shokopiwah Shaman |
 | Kiley May als Shokopiwah Woman |
 | Lisa Cromarty als Shokopiwah Woman |
 | Kevin Allan Hess als Shokopiwah Man |
 | Stephen R. Hart als Shokopiwah Man |
| Rocky L. Burnham Jr. als Shokopiwah Man |
 | Billy Merasty als Shokopiwah Man |
 | Sladen Peltier als Shokopiwah Young Boy |
 | Ari Cohen als Stanley's Dad |
 | Alex Bird als Theatre P.A. |
 | Brody Bover als Shouting Kid |
 | Edie Inksetter als Shouting Kid's Mom |
 | Martin Julien als Janitor |
 | Sonia Maria Chirila als Fishtank Girl |
| Colin Mcleod als Bully |
 | Declan Prior als Bully |
 | Marko Vujicic als Bully |
 | Eric Woolfe als Nurse |
 | Kate Corbett als Dean's Mom |
| Shawn Storer als Dean's Dad |
 | Janet Porter als Richie's Mom |
| Scott Edgecombe als Customer |
 | Anthony Ulc als The Butcher |
| J. Bogdan als Swearing Patient |
 | Louise Stratten als Audra's Assistant |
| Laura Thorne als Production Assistant |
| Thomas Duhig als Assistant Director |
 | Carla Guerrier als Police Officer |
 | Liam MacDonald als Dean's Friend |
| Chris D'Silva als Dean's Friend |
| Tristan Levi Cox als 4-Year-Old Young Mike |
| Torian Matthew Cox als 4-Year-Old Young Mike |
| Lola Del Re Hudson als Betty Ripsom's Legs |
| Thiago Dos Santos als Twitchy Man |
| Divan Meyer als Audience Member (uncredited) |
 | Andy Muschietti als Pharmacy Customer (uncredited) |
| Gary Dauberman | Screenplay |
| Stephen King | Novel |
| Andy Muschietti | Director |
| Roy Lee | Producer |
| Dan Lin | Producer |
| Nigel Churcher | Art Direction |
| Paul D. Austerberry | Production Design |
| Checco Varese | Director of Photography |
| Adam Bocknek | Second Unit Director |
| Rich Delia | Casting |
| Luis Sequeira | Costume Design |
| Shane Vieau | Set Decoration |
| Jason Ballantine | Editor |
| Shane Zander | Makeup Department Head |
| Dave Neustadter | Executive Producer |
| Marty P. Ewing | Executive Producer |
| Bárbara Muschietti | Producer |
| Richard Brener | Executive Producer |
| Seth Grahame-Smith | Executive Producer |
| David Katzenberg | Executive Producer |
| Benjamin Wallfisch | Original Music Composer |
| Penny Charter | Second Assistant Director |
| Jamie Jones | Stunt Coordinator |
| Samantha Dick | Art Department Coordinator |
| Darin Read | Associate Producer |
| Erick Ocampo | Sound Designer |
| Thomas J. O'Connell | ADR Mixer |
| Elaine Thurston | Production Accountant |
| Katharine Duke | Payroll Accountant |
| Sarah Craig McEathron | Makeup Department Head |
| Matthew Wolchock | Transportation Coordinator |
| Tamiyo Tomihiro | Costumer |
| Brooke Palmer | Still Photographer |
| Nicholas Brooks | Visual Effects Supervisor |
| Dean Stinchcombe | First Assistant "A" Camera |
| Michael Keller | Sound Re-Recording Mixer |
| John C. Stuver | ADR Editor |
| Ando Johnson | Sound Effects Editor |
| Jimmy Uddo | Visual Effects Producer |
| Mélanie Turcotte | Costumer |
| Sara Schilt | Costumer |
| Amy Sztulwark | Costumer |
| David Best | Graphic Designer |
| Jordana Lieberman | Third Assistant Director |
| Rachel Archer | Costumer |
| Jason Fuchs | Co-Producer |
| Esther Sokolow | First Assistant Editor |
| Lisa Prince | Costumer |
| Victoria Palmeri | Co-Producer |
| Lise Richardson | Music Editor |
| Katherine Rose | Foley Artist |
| Hanne Whitfield | Costumer |
| Fred Espina | First Assistant Art Direction |
| Lucas J. Wareing | First Assistant Art Direction |
| Rebecca Reed | Second Assistant Art Director |
| Jasper Vrakking | Digital Imaging Technician |
| Bruce Tanis | Sound Effects Editor |
| Cheryl Francis | Production Office Coordinator |
| Randy Morgan | Location Manager |
| Susan Nycz | Costumer |
| Christopher Geggie | Property Master |
| Michael Lerman | First Assistant Director |
| Brad Milburn | First Assistant Art Direction |
| Alexander Melvin | First Assistant Art Direction |
| Ben Turnbull | Second Assistant Art Director |
| Dawn M. Stoliar | First Assistant Editor |
| Michelle Pazer | ADR Editor |
| Kris Fenske | Sound Effects Editor |
| Shane B. Scott | Script Supervisor |
| Coco Kleppinger | Casting Associate |
| Stephanie Gorin | Local Casting |
| Rob Beal | Sound Mixer |
| Peter S. Elliot | Additional Editor |
| Bill R. Dean | Supervising Sound Editor |
| Jessie Pariseau | Sound Effects Editor |
| Lisa Shamata | Unit Publicist |
| Craig Seitz | Third Assistant Director |
| Ann Steel | Assistant Costume Designer |
| Nathalie Gysel | Costumer |
| Linda Dowds | Makeup Artist |
| Carol Hartwick | Key Hair Stylist |
| William Waring | Second Unit Director |
| David G. Fremlin | First Assistant Art Direction |
| Angelo Colavecchia | "A" Camera Operator |
| Matthew Reid | Second Assistant "A" Camera |
| Sylvain Arseneault | Sound Mixer |
| Randy Torres | Sound Designer |
| Michelle Pazer | Dialogue Editor |
| Randy Singer | Foley Mixer |
| Anita Bacic | Costumer |
| Christina Cattle | Costumer |
| Gary Dauberman | Executive Producer |
| Anna Beben | Unit Production Manager |
| Michael Carella | "B" Camera Operator |
| Alastair Muir | Key Makeup Artist |
| Daryl Purdy | Sound Mixer |
| Randy Starr | Visual Effects Producer |
| Debbie Williams | Costumer |
| Ying Zhao | Costumer |
| Alec Gillis | Makeup Designer |
| Sondra Treilhard | Key Hair Stylist |
| Sorin Popescu | First Assistant Art Direction |
| Ryan Longo | Boom Operator |
| Tim LeBlanc | Sound Re-Recording Mixer |
| Nancy Nugent | Supervising Sound Editor |
| Catherine Harper | Foley Artist |
| Suzanne Aplin | Costume Supervisor |
| Miranda Lukaniuk | Costumer |
| Tom Woodruff Jr. | Makeup Designer |
| Stephanie Ingram | Hair Designer |
| Warren Appleby | Special Effects Coordinator |
| Marty P. Ewing | Unit Production Manager |
| John C. Stuver | Dialogue Editor |
| Oriana Rossi | Makeup Artist |
| Ryan Reed | Hair Department Head |
| Kay Rogers | Background Casting Director |
| Teresa Leong | Digital Compositor |
| Jeremy Gillespie | Graphic Designer |
| Nick Alachiotis | Stunts |
| Alex Armbruster | Stunts |
| Derek Barnes | Stunts |
| Marco Bianco | Stunts |
| James Binkley | Stunts |
| Matt Birman | Stunts |
| Christine Cleary | Stunts |
| Tim Cody | Stunts |
| Neil Davison | Stunts |
| Amanda Dellapenta | Stunts |
| Dustin Faith | Stunts |
| Tom Farr | Stunts |
| Cam Fergus | Stunts |
| Steve Gagne | Stunts |
| Jason Gosbee | Stunts |
| Brayden Jones | Stunts |
| Brent Jones | Stunts |
| Brook Jones | Stunts |
| Ciara Jones | Stunts |
| Dana Jones | Stunts |
| Kelly Jones | Stunts |
| Dennis Lafond | Stunts |
| Daniel Lavigne | Stunts |
| Torianna Lee | Stunts |
| Patrick Mark | Stunts |
| Cotton Mather | Stunts |
| Geoff Meech | Stunts |
| Regan Moore | Stunts |
| Daryl Patchett | Stunts |
| Edward A. Queffelec | Stunts |
| Aj Risi | Stunts |
| Vincent Rother | Stunts |
| Steve 'Shack' Shackleton | Stunts |
| Geoff Scovell | Stunts |
| Dan Skene | Stunts |
| John Stead | Stunts |
| Amy Szoke | Stunts |
| Al Vrkljan | Stunts |
| Wayne Wells | Stunts |
| Mark Purcell | Sound Mix Technician |
| Danielle Carney | Visual Effects Coordinator |
| Amanda H. Campbell | Visual Effects Coordinator |
| Cole Darby | Visual Effects Coordinator |
| Candace Tempelmeyer | First Assistant Accountant |
| Richard Emerson | Key Grip |
| John Mackenzie | Construction Coordinator |
| Roberto Campanella | Choreographer |
| Stephen Nakamura | Digital Intermediate Colorist |
| Vanessa Galvez | Digital Intermediate Producer |
| Josh Simmonds | Visual Effects Supervisor |
| Ineke Majoor | Visual Effects Producer |
| Warren Appleby | In Memory Of |
| Brooke Lyndon-Stanford | Visual Effects Supervisor |
| Liam Kiernan | Assistant Location Manager |
