- Guy Williams
- Â Dr. John Robinson 84 episodes, 1965-1968
- June Lockhart
- Â Maureen Robinson 84 episodes, 1965-1968
- Mark Goddard
- Â Major Don West 84 episodes, 1965-1968
- Marta Kristen
- Â Judy Robinson / ... 84 episodes, 1965-1968
- Bill Mumy
- Â Will Robinson 84 episodes, 1965-1968
- Angela Cartwright
- Â Penny Robinson / ... 84 episodes, 1965-1968
- Jonathan Harris
- Â Dr. Zachary Smith / ... 83 episodes, 1965-1968
- Dawson Palmer
- Â Monster / ... 5 episodes, 1965-1967
- Jim Mills
- Â Saticon #1 / ... 1 episode, 1966-1968
- Harry Monty
- Â Geoo / ... 1 episode, 1966-1968
- Dee Hartford
- Â Verda / ... 3 episodes, 1966-1968
- Fritz Feld
- Â Mr. Zumdish 3 episodes, 1966-1967
- Sheila Allen
- Â Aunt Gamma / ... 3 episodes, 1965-1968
- Ron Gans
- Â Alien Leader / ... 2 episodes, 1966-1967
- Ronald Weber
- Â Alien Dictator / ... 1 episode, 1966-1968
- Albert Salmi
- Â Alonzo P. Tucker / ... 2 episodes, 1966-1967
- Vitina Marcus
- Â Athena / ... 2 episodes, 1966-1967
- Michael Rennie
- Â The Keeper 2 episodes, 1966
- Leonard Stone
- Â Farnum 2 episodes, 1967-1968
- Robert Foulk
- Â Cragmire / ... 2 episodes, 1967-1968
- Marcel Hillaire
- Â Junkman / ... 2 episodes, 1967-1968
- Don Matheson
- Â IDAK Alpha 12 / ... 2 episodes, 1965-1967
- Tiger Joe Marsh
- Â Elevator Operator / ... 2 episodes, 1966-1967
- Keith Taylor
- Â Edgar / ... 2 episodes, 1965-1968
- Allan Melvin
- Â Enforcer Claudio / ... 1 episode, 1966
- Hoke Howell
- Â Security Guard / ... 1 episode, 1965-1968
- Larry Dean
- Â Mummy / ... 1 episode, 1967
- Warren Oates
- Â Jimmy Hapgood 1 episode, 1965
- Reta Shaw
- Â Aunt Clara Simms 1 episode, 1965
- Michael J. Pollard
- Â The Boy 1 episode, 1966
- Michael Ansara
- Â The Ruler 1 episode, 1966
- Royal Dano
- Â Major Domo 1 episode, 1966
- Werner Klemperer
- Â Bolix 1 episode, 1966
- Strother Martin
- Â Nerim 1 episode, 1966
- James Westerfield
- Â Dr. Marvello 1 episode, 1966
- Gerald Mohr
- Â Morbus 1 episode, 1966
- Liam Sullivan
- Â Nexus 1 episode, 1966
- Mercedes McCambridge
- Â Sybilla 1 episode, 1966
- Henry Jones
- Â Jeremiah Smith 1 episode, 1966
- Wally Cox
- Â Tiabo 1 episode, 1966
- Mike Kellin
- Â Myko 1 episode, 1966
- Torin Thatcher
- Â The Space Trader 1 episode, 1966
- Dennis Patrick
- Â Keema 1 episode, 1966
- Malachi Throne
- Â Thief 1 episode, 1966
- John Abbott
- Â Sesmar 1 episode, 1966
- John Carradine
- Â Arcon 1 episode, 1967
- Francine York
- Â Niolani 1 episode, 1967
- Hans Conried
- Â Sagramonte 1 episode, 1967
- Daniel J. Travanti
- Â Space Hippie 1 episode, 1967
- Al Lewis
- Â Zalto 1 episode, 1967
- Walter Burke
- Â Mr. O. M. 1 episode, 1967
- Woodrow Parfrey
- Â Colonel Silas Fogey 1 episode, 1967
- Alan Hewitt
- Â Lemnoc 1 episode, 1967
- Vincent Beck
- Â Megazor 1 episode, 1967
- Sean McClory
- Â Hamish 1 episode, 1967
- Arthur Batanides
- Â Rangah 1 episode, 1967
- Ronald Long
- Â Admiral Zahrk 1 episode, 1967
- Lew Gallo
- Â Commander Fletcher 1 episode, 1967
- Tommy Farrell
- Â Cyborg 1 episode, 1967
- Grant Sullivan
- Â Alien #764 1 episode, 1967
- Alberto Monte
- Â Chavo 1 episode, 1967
- John Crawford
- Â Dr. Chronos 1 episode, 1968
- Michael Conrad
- Â Creech 1 episode, 1968
- Stanley Adams
- Â Tybo 1 episode, 1968
- Abraham Sofaer
- Â Sobram 1 episode, 1968
- Gil Rogers
- Â Bartholomew 1 episode, 1968
- Jim Gosa
- Â Gilt Proto 1 episode, 1968
- Walter Sande
- Â Sheriff George Baxendale 1 episode, 1965
- Françoise Bush
- Â Moela 1 episode, 1965
- Kurt Russell
- Â Quano 1 episode, 1966
- Kym Karath
- Â Princess 1 episode, 1966
- Sherry Jackson
- Â Effra 1 episode, 1966
- Ted Cassidy
- Â Slave 1 episode, 1966
- Kevin Hagen
- Â Alien 1 episode, 1966
- Peter Brocco
- Â Alien Leader 1 episode, 1966
- Melinda O. Fee
- Â Fenestra 1 episode, 1966
- Larry Ward
- Â Ohan 1 episode, 1966
- Mickey Manners
- Â Dee 1 episode, 1966
- Lyle Waggoner
- Â Mechanical Man I 1 episode, 1967
- Linda Gaye Scott
- Â Alien Girl 1 episode, 1967
- Lou Wagner
- Â J-5 1 episode, 1967
- Corinna Tsopei
- Â Princess Reyka 1 episode, 1967
- Jim Boles
- Â Smeek 1 episode, 1967
- Pitt Herbert
- Â Grover 1 episode, 1967
- Bern Hoffman
- Â Thor 1 episode, 1967
- Don Eitner
- Â Sergeant Horatio Smith 1 episode, 1967
- Harry Raybould
- Â Urso 1 episode, 1967
- Carol Williams
- Â Alien #1220 1 episode, 1967
- Richard Krisher
- Â MXR 1 episode, 1967
- Arte Johnson
- Â Fedor 1 episode, 1968
- James Millhollin
- Â Willoughby the Llama 1 episode, 1968
- Charles Horvath
- Â Guard #1 1 episode, 1968
- Byron Morrow
- Â General Squires 1 episode, 1968
- Tol Avery
- Â Warden 1 episode, 1968
- Ken Mayer
- Â Pleiades Pete 1 episode, 1966
- Bill Troy
- Â Handsome Alien 1 episode, 1966
- Claire Wilcox
- Â Stacy 1 episode, 1967
- Gary Tigerman
- Â Oggo 1 episode, 1967
- Kenya Coburn
- Â Zaybo 1 episode, 1967
- Ralph Lee
- Â Mechanical Man II 1 episode, 1967
- Eric Matthews
- Â QZW 1 episode, 1967
- Miriam Schiller
- Â Miss Teutonium 1 episode, 1968
- Robert Easton
- Â Newsman Lacy 1 episode, 1965
- Michael Greene
- Â Nubu 1 episode, 1966
- Edy Williams
- Â NON 1 episode, 1967
- Norman Leavitt
- Â Charlie 1 episode, 1967
- Harry Harvey
- Â Grover 1 episode, 1965
- Robert Pine
- Â Craig 1 episode, 1967
- Carroll Roebke
- Â TAT 1 episode, 1967
- Helen Kleeb
- Â Phone Operator Rachel 1 episode, 1965
- Anne Dore
- Â First Selectman 1 episode, 1965
- Donald Losby
- Â Davey Sims 1 episode, 1965
- Johnny Tuohy
- Â First Boy (the tall, thin blonde) 1 episode, 1965
- Dick Tufeld
- Â The Robot / ... (uncredited) 84 episodes, 1965-1968
- Bob May
- Â The Robot (uncredited) 82 episodes, 1965-1968
- Judy the Chimpanzee
- Â Debbie the Bloop (uncredited) 11 episodes, 1965-1967
- John Hunt
- Â Saticon #2 / ... (uncredited) 7 episodes, 1966-1968
- Joe E. Tata
- Â Computer Eye / ... (uncredited) 5 episodes, 1967
- Paul Kessler
- Â Saticon #3 / ... (uncredited) 4 episodes, 1966-1968
- Bart La Rue
- Â Alien #2 / ... (uncredited) 4 episodes, 1967-1968
- Fred Krone
- Â Alien Monster / ... (uncredited) 4 episodes, 1967-1968
- Jeffrey Trayler
- Â Alien Soldier #2 / ... (uncredited) 4 episodes, 1967-1968
- Paul Zastupnevich
- Â Bearded Foreign Correspondent / ... (uncredited) 3 episodes, 1965-1967
- Don Forbes
- Â TV Commentator (uncredited) 3 episodes, 1965
- Robby the Robot
- Â Robotoid / ... (uncredited) 3 episodes, 1966-1967
- Mike Donovan
- Â Hades Monster / ... (uncredited) 3 episodes, 1966
- Frank Parker
- Â Security Guard (uncredited) 2 episodes, 1965-1968
- William Bramley
- Â Mr. Nobody / ... (uncredited) 2 episodes, 1965-1966
- Janos Prohaska
- Â Giant Bird Monster / ... (uncredited) 2 episodes, 1965-1966
- Theodore Lehmann
- Â Alien / ... (uncredited) 2 episodes, 1965-1966
- Ford Rainey
- Â The President (uncredited) 2 episodes, 1965
- Robert 'Big Buck' Maffei
- Â The Giant Cyclops (uncredited) 2 episodes, 1965
- Lamar Lundy
- Â The Giant / ... (uncredited) 2 episodes, 1965
- Sue England
- Â Female Robot / ... (uncredited) 2 episodes, 1966-1967
- Michael Fox
- Â Alien on Computer Screen / ... (uncredited) 2 episodes, 1966-1967
- Eldon Hansen
- Â Robot Guard / ... (uncredited) 2 episodes, 1966-1967
- Gregory Morton
- Â Canto of Quasti / ... (uncredited) 2 episodes, 1966
- Wilbur Evans
- Â Lighted Head Leader (uncredited) 2 episodes, 1966
- Ralph Madlener
- Â Monster #2 / ... (uncredited) 2 episodes, 1968
- Charles Dierkop
- Â Horned Mutant (uncredited) 1 episode, 1965
- Richard Basehart
- Â Shakespeare-Reading Tape Recorder Voice (uncredited) 1 episode, 1965
- Fred Crane
- Â Alpha Control Technician (uncredited) 1 episode, 1965
- Eddie Rosson
- Â Lunon (uncredited) 1 episode, 1965
- Hal Torey
- Â General (uncredited) 1 episode, 1965
- Tom Allen
- Â Inspector (uncredited) 1 episode, 1965
- Joe Ryan
- Â Luminary (uncredited) 1 episode, 1965
- Eddie Quillan
- Â Bartender (uncredited) 1 episode, 1966
- Chuck Roberson
- Â Alien Fighter (uncredited) 1 episode, 1966
- Lane Bradford
- Â Barfly (uncredited) 1 episode, 1966
- Charles Morton
- Â Barfy (uncredited) 1 episode, 1966
- Ollie O'Toole
- Â Robotoid (uncredited) 1 episode, 1966
- Maxine Gates
- Â Fat Princess (uncredited) 1 episode, 1966
- Hal Jon Norman
- Â Dog-faced Alien (uncredited) 1 episode, 1966
- Frank Graham
- Â Alien (uncredited) 1 episode, 1966
- Eddie Quinlan
- Â Bartender (uncredited) 1 episode, 1966
- Charles Arthur
- Â Smith's Double (uncredited) 1 episode, 1966
- Harry Varteresian
- Â Vicho (uncredited) 1 episode, 1966
- June Foray
- Â Gundemar (uncredited) 1 episode, 1967
- Duke Fishman
- Â Convict (uncredited) 1 episode, 1967
- Frank Delfino
- Â Troll of Niffelheim (uncredited) 1 episode, 1967
- Stephan Merjanian
- Â Alien Hippie #4 (uncredited) 1 episode, 1967
- Gil Perkins
- Â Convict (uncredited) 1 episode, 1967
- Ben Frommer
- Â Convict (uncredited) 1 episode, 1967
- Zamba
- Â The Lion (uncredited) 1 episode, 1967
- Lars Hensen
- Â Convict (uncredited) 1 episode, 1967
- Craig Duncan
- Â Deek (uncredited) 1 episode, 1967
- Craig Chudy
- Â Alien Soldier #3 (uncredited) 1 episode, 1967
- Mike Morelli
- Â Convict (uncredited) 1 episode, 1967
- Orwin C. Harvey
- Â Third Alien Guard (uncredited) 1 episode, 1967
- Joey Russo
- Â Young Smith (uncredited) 1 episode, 1967
- Dave Dunlap
- Â First Alien Guard (uncredited) 1 episode, 1967
- Jeff County
- Â Gundemar (uncredited) 1 episode, 1967
- Erwin Niel
- Â Second Alien Guard (uncredited) 1 episode, 1967
- Maritza Elsen
- Â Alien Soldier #1 (uncredited) 1 episode, 1967
- Rita Fabotta
- Â Alien Soldier #4 (uncredited) 1 episode, 1967
- Seymour Konic
- Â Fourth Alien Guard (uncredited) 1 episode, 1967
- Brent Davis
- Â Mike Officer (uncredited) 1 episode, 1968
- Thant Brann
- Â Officer (uncredited) 1 episode, 1968