Keir Dullea as Dr. David Bowman

Gary Lockwood as Dr. Frank Poole

William Sylvester as Dr. Heywood Floyd

Douglas Rain as HAL 9000 (voice)

Daniel Richter as Moonwatcher

Leonard Rossiter as Dr. Andrei Smyslov

Margaret Tyzack as Elena

Robert Beatty as Dr. Ralph Halvorsen

Sean Sullivan as Dr. Roy Michaels

Frank W. Miller as Mission Controller (voice)

Bill Weston as Astronaut

Ed Bishop as Aries-1B Lunar Shuttle Captain

Glenn Beck as Astronaut

Alan Gifford as Poole's Father

Ann Gillis as Poole's Mother

Edwina Carroll as Aries-1B Stewardess

Penny Brahms as Stewardess

Heather Downham as Stewardess

Mike Lovell as Astronaut

John Ashley as Ape

Jimmy Bell as Ape

David Charkham as Ape

Keith Denny as Ape

Jonathan Daw as Ape

Péter Delmár as Ape

Terry Duggan as Ape Attacked by Leopard

David Fleetwood as Ape

Danny Grover as Ape

Brian Hawley as Ape

David Hines as Ape

Anthony Jackson as Ape

John Jordan as Ape

Scott MacKee as Ape

Laurence Marchant as Ape

Darryl Paes as Ape

Joe Refalo as Ape

Andy Wallace as Ape

Bob Wilyman as Ape

Richard Woods as Ape Killed by Moon-Watcher

Maggie London as Hostess in Elevator (uncredited)

Chela Matthison as Receptionist (uncredited)

Judy Keirn as Voice Print Identification Girl (uncredited)

Vivian Kubrick as Floyd's Daughter (uncredited)

Kenneth Kendall as BBC-12 Announcer (uncredited)

Kevin Scott as Miller (uncredited)

Martin Amor as Interviewer (uncredited)

S. Newton Anderson as Young Man (uncredited)

Sheraton Blount as (uncredited)

Ann Bormann as (uncredited)

Julie Croft as (uncredited)

Penny Francis as (uncredited)

Marcella Markham as (uncredited)

Irena Marr as Russian Scientist (uncredited)

Krystyna Marr as Russian Scientist (uncredited)

Kim Neil as (uncredited)

Jane Pearl as (uncredited)

Penny Pearl as (uncredited)

Burnell Tucker as TMA-1 Site Photographer (uncredited)

John Swindells as TMA-1 Site Technician #1 (uncredited)

John Clifford as TMA-1 Site Technician #2 (uncredited)

Stanley Kubrick as Astronaut Breathing (voice) (uncredited)

Harry Fielder as Moonwalker (uncredited)

John Ashley as Ape