Gregory Peck
Robert Thorn
Lee Remick
Katherine Thorn
David Warner
Keith Jennings
Billie Whitelaw
Mrs. Baylock
Harvey Stephens
Damien
Patrick Troughton
Father Brennan
Martin Benson
Father Spiletto
Robert Rietti
Monk
Tommy Duggan
Priest
John Stride
Psychiatrist
Holly Palance
Young Nanny
Anthony Nicholls
Dr. Becker
Roy Boyd
Reporter
Sheila Raynor
Mrs. Horton
Robert MacLeod
Horton
Bruce Boa
Thorn's Aide
Don Fellows
Thorn's Second Aide
Patrick McAlinney
Photographer
Dawn Perllman
Chambermaid
Nancy Mannigham
Nurse
Miki Iveria
First Nun
Betty McDowall
American Secretary
Nicholas Campbell
Marine
Burnell Tucker
Secret Service Man (uncredited)
Ronald Leigh-Hunt
Gentleman at Rugby Match (uncredited)
Guglielmo Spoletini
Italian Taxi Driver (uncredited)
Freda Dowie
Nun (uncredited)
Ya'ackov Banai
Arab (uncredited)
Harvey Bernhard
Man walking across street (uncredited)
Michael Byrne
Monk (uncredited)
Leo McKern
Carl Bugenhagen (uncredited)
Bill Reimbold
General (uncredited)
Michael Leader
Rugby Match Spectator (uncredited)