 | Ross Lynch als Jeffrey Dahmer |
 | Alex Wolff als John 'Derf' Backderf |
 | Anne Heche als Joyce Dahmer |
 | Dallas Roberts als Lionel Dahmer |
 | Liam Koeth als Dave Dahmer |
 | Nancy Telzerow als Carol Backderf |
 | Tommy Nelson als Neil |
 | Harrison Holzer als Mike |
| Brigid Naughton als Melody |
 | Cameron McKendry als Moose |
| Katie Stottlemire als Penny |
| Brady M.K. Dunn als Bossy |
| Jake Ingrassia als Gooch |
| Michael Ryan Boehm als Shorty |
| Ben Zgorecki als Bully Jock |
| Dontez James als Charlie Smith |
 | Miles Robbins als Lloyd Figg |
| Gabriela Novogratz als Lisa Watkins |
| Jack DeVillers als Oliver Zlatka |
| Dave Sorboro als Steven Hicks |
| Joey Prines als Snarky Slacker |
| Kris Smith als Ms Bowles |
 | Adam Kroloff als Mr Burlman |
 | Christopher Mele als Mr Fedele |
| Joey Vee als Mr Hicks |
| Tom Lepera als Mr Lapolla |
 | Vincent Kartheiser als Dr Matthews |
 | Maryanne Nagel als Mrs Woodard |
| Sydney Meyer als Bridget |
| Lauren Rhodes als Aide |
| Tom Luce als Vice President Walter Mondale |
 | Carmen Gangale als Grocery Store Manager |
| Shane Patrick O'Neill als Restaurant Manager |
 | Joe Fishel als Market Shopper |
 | Andrew Gorell als English Teacher |
| Susan Bennett als Musical Director |
| Nicholas Hulstine als Prom Photographer |
| Zachary Davis Brown als Freshman Boy |
| Lily Kozub als Freshman Girl |
| Clayton Frank als Bus Student 1 (uncredited) |
| Marc Meyers | Director |
| Daniel Katz | Director of Photography |
| Jamie Kirkpatrick | Editor |
| Jennifer Klide | Production Design |
| Stephanie Holbrook | Casting |
| Andrew Hollander | Original Music Composer |
| Jody Girgenti | Producer |
| Adam Goldworm | Producer |
| Michael Merlob | Producer |
| Marc Meyers | Producer |
| William K. Baker | Co-Producer |
| Gabriela Novogratz | Associate Producer |
| Giorgio Angelini | Executive Producer |
| Michael Novogratz | Executive Producer |
| Ed McWilliams | Co-Executive Producer |
| John S. Novogratz | Co-Executive Producer |
| Carmen Navis | Set Decoration |
| Carla Shivener | Costume Design |
| Jacquelyn Adamson | Makeup Department Head |
| Kristephan Warren-Stevens | Makeup Artist |
| La Toyia N. Bankhead | Hairstylist |
| Korrey Robinson | Hairstylist |
| Thomas Terhaar | Hair Department Head |
| Derf Backderf | Comic Book |
| Marc Meyers | Screenplay |
| Milan Chakraborty | Producer |
| Coll Anderson | Supervising Sound Editor |
| Coll Anderson | Sound Re-Recording Mixer |
| Paddy Hanlon | Sound Mixer |
| Tami Kumin | Second Assistant Director |
| Andrew Shepherd | First Assistant Director |
| Courtne Benson | Assistant Property Master |
| Michael Scott Manne | Graphic Designer |
| Kelleigh Miller | Property Master |
| Monica Plunkett | Assistant Property Master |
| Grace Smith | Art Department Coordinator |
| Teresa Strebler | Assistant Set Decoration |
| Duncan Clark | Dialogue Editor |
| Jay Peck | Foley Artist |
| Matt Snedecor | Sound Effects Editor |
| Stewart Cantrell | Steadicam Operator |
| Travis Cleary | First Assistant "A" Camera |
| Chris Cogan | Dolly Grip |
| Tim Figueira | Electrician |
| Kyle Gorjanc | Second Assistant Camera |
| Daniel M. Henterly | Still Photographer |
| Jordan Pellegrini | Second Assistant Camera |
| Donnie Schneider | Key Grip |
| Rick Stern | Best Boy Grip |
| John Turk | Gaffer |
| Rana Mancini Cavanaugh | Key Costumer |
| Rebecca DeNoewer | Costume Supervisor |
| Shawna-Nova Foley | Assistant Costume Designer |
| Carolyn Cury | Digital Intermediate Producer |
| Darryl Dickenson | Assistant Editor |
| Anthony Muzzatti | Assistant Editor |
| Frank Reynolds | Additional Editor |
| Jasmin Way | Assistant Editor |
| Kathy Ruggeri | Location Manager |
| Jonathan Leahy | Music Supervisor |
| David J. Lawson | Assistant Production Coordinator |
| Andrew Rathbone | Production Secretary |
