Robert Downey Jr. as Sherlock Holmes

Jude Law as Dr. John Watson

Rachel McAdams as Irene Adler

Mark Strong as Lord Henry Blackwood

Eddie Marsan as Inspector Lestrade

Robert Maillet as Dredger

Geraldine James as Mrs. Hudson

Kelly Reilly as Mary Morstan

William Houston as Constable Clark

Hans Matheson as Lord Coward

James Fox as Sir Thomas Rotheram

William Hope as Ambassador Standish

Clive Russell as Captain Tanner

Oran Gurel as Reordan

David Garrick as McMurdo

Ky Discala as Maid

Andrew Brooke as Guard Captain

Tom Watt as Carriage Driver

John Kearney as Carriage Driver

Sebastian Abineri as Coach Driver

Jonathan Gabriel Robbins as Guard

James A. Stephens as Captain Philips

Terence Taplin as Groundskeeper

Bronagh Gallagher as Palm Reader

Ed Tolputt as Anonymous Man

Joe Egan as Big Man

Jefferson Hall as Young Guard

Miles Jupp as Waiter

Marn Davies as Police Officer

Andrew Greenough as Prison Guard

Ned Dennehy as Man with Roses

Martin Ewens as Removable Man

Amanda Grace Johnson as Young Woman Sacrifice

James Greene as Governor

David Emmings as Grave Policeman

Ben Cartwright as Grave Policeman

Chris Sunley as Grave Policeman

Michael Jenn as Preacher

Timothy O'Hara as Porter / Smith

Guy Williams as Golden Dawn Envoy

Peter Miles as Thug

Rocco Ritchie as Boy in the Street (uncredited)