| Will Ferrell | Holmes |
| John C. Reilly | Watson |
| Rebecca Hall | Dr. Grace Hart |
| Rob Brydon | Inspector Lestrade |
| Kelly MacDonald | Mrs. Hudson |
| Lauren Lapkus | Millie |
| Ralph Fiennes | Moriarty |
| Hugh Laurie | Mycroft |
| Noah Jupe | Doxy |
| Steve Coogan | Actor |
| Pam Ferris | Queen Victoria |
| Adam Scherr | Wrestler |
| Bella Ramsey | Flotsam |
| Wolf Roth | Sigmund Freud |
| Bronson Webb | Jonathan Nightingale |
| Kieran O'Brien | PC Smalls |
| Michael Culkin | Judge Over |
| Clare Foster | Lady Stepping |
| Willem Dalby | Newsie Man |
| Billy Jenkins | Mudfog |
| Scarlet Grace | Pickle |
| Gerard Monaco | Officer |
| Jorge Leon Martinez | British Soldier |
| Jordan Long | Herbert |
| James Eeles | Manager Mr. Petrucka |
| Paddy Holland | Tough Kid |
| Karl Farrer | Russian Merchant |
| Hector Bateman-Harden | Young Sherlock Holmes |
| Jason Thorpe | Butler |
| Amelia O'Loughlin | White Star-Line Girl |
| Oliver Maltman | Telegraph Operator |
| Riley White | Newsie Kid-Jimmy |
| Christian Wolf-La'Moy | English Gentleman |
| Ella Bright | Bridgette |
| Ethan Rouse | Newsreader |
| Adam Ward | Steve - Queen's Royal Guard |
| Anthony M. Dawson | Beefeater #1 |
| Joseph Macnab | Fitness Instructor |
| Deepak Anand | Nobleman |
| Matthew DiLiello | Telly-Phone Assistant |
| Lochlan White | Newsie Kid-Timmy |
| Daniel Fearn | The Drooling Man |
| Paul Cassidy | Charlie Chaplin |
| Benjamin Lok | Courtroom Person 3 |
| Tommy Surridge | Tough Kid 2 |
| Shawn Dixon | Upper Class Gentleman #1 |
| Laura Stevely | Sherlock's Mother |
| Russell Wilcox | The Announcer |
| Phil Hodges | Mr. Algernon Barkworth |
| Layla Rose Boyce | Tough Kid |
| David Stoller | Guard (Southhampton) |
| Lindy Barrett | School Girl |
| Sonnyboy Skelton | Doxy's Dad |
| Martyn Mayger | Buckingham Palace Guest |
| David Handley | Executioner |
| Sara Beasley | Mrs. Frobisher |
| Mick Slaney | Docker |
| Codie-Lei Eastick | Young Watson |
| Jamie Baughan | Titanic Captain |
| Paul T.T. Easter | John |
| Craig Thomas Lambert | Yeoman of the Guard |
| John Kinory | Instructing Solicitor |
| Stanley Eldridge | Waiter 2 |
| David Shackleton | Albert Einstein |
| Colby Mulgrew | Haybag |
| Henrihs Ahmadejevs | Drunk |
| Martin Bassindale | One Man Band |
| Anthony Richard Rowe | Victorian Gentleman |
| Ellie Rose Eames | Newschild |
| Joey Grima | Queen Victoria's Grenadier Guard |
| Darren Lake | Disoriented Man |
| Edward Olhausen | Street Urchin |
| Wesley Kent-Hargreaves | The Weird Child |
| Neil Main | Screaming Soldier |
| David Bromley | Phone Guy |
| Mark Behan | Ringside Bookie |
| Angus Cook | Policeman |
| Samuel Dunning | Queens Footman |
| Anjan Kannan | Townsfolk |
| Samantha Sharon Watson | Elizabeth - Lady of the Night |
Technical Credits
| Etan Cohen | Director,Screenwriter |
| Christophe Beck | Score Composer |
| Adrian Bell | Sound Mixer |
| Toby Britton | Art Director |
| Tilly Calder | Makeup |
| Jamie Christopher | Asst. Director,Co-producer |
| Jamie Christopher | Asst. Director,Co-producer |
| Jessica Elbaum | Executive Producer |
| Will Ferrell | Producer |
| Renata Gilbert | Makeup |
| Jonah Goldfinger | Associate Producer |
| Katie Halliday | Sound Editor |
| James Hambidge | Production Designer |
| Chris Henchy | Executive Producer |
| Erik Jessen | Editor |
| Adam McKay | Producer |
| Jimmy Miller | Producer |
| David Mimran | Executive Producer |
| Mark Mothersbaugh | Score Composer |
| Beatrix Aruna Pasztor | Costumes/Costume Designer |
| Stewart Probert | Production Manager |
| M. Riley | Executive Producer |
| Jordan Schur | Executive Producer |
| Lucinda Syson | Casting |
| Clayton Townsend | Producer |
| Su Whitaker | Art Director |
| Haley J. Williams | Special Effects Supervisor |
| Oliver Wood | Cinematographer |
| Christopher Wyatt | Art Director |
| Dean Zimmerman | Editor |
