Simon Oates
- Tully
Steve Oatway
- Supervisor
Barack Obama
- Himself (archive footage)
John O'Brien
- Second Missionary
Tom O'Brien
- Sergeant Lewis Frisch
Sean O'Byrne
- Second Officer
Benjamin Ochieng
- Second African Man
Patrick O'Connell
- Manton
Stuart O'Connell
- First SWAT Officer
- First Officer
Brent CS O'Connor
- Tow Truck Driver
Derrick O'Connor
- Jack Stone
Paul Vincent O'Connor
- Superintendent Brian Hutchinson
Annie O'Donnell
- Tahoma [Elderly Woman]
Conor O'Farrell
- Sheriff Ciolino
Fionn O'Farrell
- Nurse
Randy Oglesby
- Reverend Samuel Mackey
Tim O'Halloran
- Patrolman
- Sergeant
Gerry O'Hara
- Director
Maggie O'Hara
- Young Woman
Terrence O'Hara
- Director
Kevan Ohtsji
- Toshiro
John O'Hurley
- Dr Francis Pollidori
Shannon O'Hurley
- Anne Voss
Anthony Okungbowa
- Dr Barnes' Driver
Amanda O'Leary
- Doctor
William O'Leary
- Gas Station Man
John Oliver
- Rolston
Ty Olsson
- Young Orderly
Casey C O'Neill
- Cemetery Grounds Keeper
Michael O'Neill
- Patrol Captain Van Gelder
Carrick O'Quinn
- Second Primitive
Terry O'Quinn
- Lieutenant Brian Tillman
- Special Agent Darius Michaud
- Shadow Man
Cyril O'Reilly
- Ed Kelso
Tom O'Rourke
- Steve Humphreys
Leland Orser
- Jason Ludwig
Marilyn Osborn
- Writer
Holmes Osbourne
- Mike Johnson [The Necromancer]
Kevin O'Shea
- Dr Dyson
Michael O'Shea
- Lieutenant Madson
Tony Osoba
- Martin Taylor [Handsome Negro]
Mary Ostrow
- Nurse McCaslin
James Otis
- Arlen Sacks
Scott Oughterson
- Old Orderly
Levani Outchaneichvili
- John Mostow
Horace Ové
- Director
Glyn Owen
- Barry Martin
Nicholas Owen
- Jones
Roger Owen
- Driver
Chris Owens
- Young Smoking Man
- The Great Mutato
John Owens
- Johnson
Kenneth Owens
- Groves
Shelley Owens
- Tessa Sears