Angela Cartwright

Penny Robinson

Guy Williams

Dr. John Robinson

June Lockhart

Dr. Maureen Robinson

Mark Goddard

Major Don West

Marta Kristen

Judy Robinson

Bill Mumy

Will Robinson

Jonathan Harris

Dr. Zachary Smith

Dick Tufeld

Robot B-9

Bob May

Robot B-9

Dawson Palmer

Monster

Fritz Feld

Mr. Zumdish

Sheila Allen

Brynhilda

Ron Gans

Frog Alien (voice)

Dee Hartford

Verda

Leonard Stone

Farnum

Albert Salmi

Captain Alonzo P. Tucker

Michael Rennie

The Keeper

Vitina Marcus

Athena

Michael Fox

Cybernetic Leader / Supreme Brain (voice)

Don Matheson

Rethso

Joe E. Tata

Zalto's Dummy (voice)

Don Forbes

TV Commentator

Theodore Lehmann

Alien

Gregory Morton

Judge Iko (voice)

Allan Melvin

Little Joe / Gambling Machine (voice)

Tiger Joe Marsh

Elevator Operator

Hoke Howell

Security Guard

Sue England

Space Control Officer O-3 (voice)

Keith Taylor

Edgar

Robert Foulk

Cragmire

Marcel Hillaire

Phanzig

Fred Krone

Chronos' Alien Assistant

Ted Cassidy

Slave

Melinda O. Fee

Fenestra

Wally Cox

Tiabo

Dennis Patrick

Keema

Strother Martin

Nerim

Mike Kellin

Myko

Henry Jones

Jeremiah Smith

Gerald Mohr

Morbus

Mickey Manners

Dee

Torin Thatcher

The Space Trader

Michael J. Pollard

The Boy

Michael Ansara

The Ruler

Hans Conried

Sagramonte

Wilbur Evans

Lighted Head Leader

Lamar Lundy

The Giant Cyclops

John Carradine

Arcon

Sean McClory

Hamish

Al Lewis

Zalto

Francine York

Niolani

Werner Klemperer

Bolix

Warren Oates

Jimmy Hapgood

Robert Easton

Newsman Lacy

Frank Delfino

Ronald Long

Admiral Zahrk

Kevin Hagen

Alien

Lew Gallo

Cmdr. Fletcher

Arthur Batanides

Rongah

Kym Karath

Princess

Lyle Waggoner

Mechanical Man

Daniel J. Travanti

Space Hippie

Stanley Adams

Tybo

Vincent Beck

Megazor

Abraham Sofaer

Sobram

Mercedes McCambridge

Sybilla

Michael Conrad

Creech

Lou Wagner

J-5

John Crawford

Dr. Chronos

Eddie Quillan

Bartender

Malachi Throne

Thief

Walter Burke

O. M.

Peter Brocco

Alien Leader

Janos Prohaska

Bird Monster

James Westerfield

Dr. Marvello

Kurt Russell

Quano

Larry Ward

Ohan

Reta Shaw

Aunt Clara Simms

John Abbott

Sesmar

Sherry Jackson

Effra

Arte Johnson

Fedor

Tol Avery

Warden

Liam Sullivan

Nexus

Royal Dano

Major Domo

Woodrow Parfrey

Col. Silas Fogey

Edy Williams

Non

Chuck Roberson

Alien Fighter

Lane Bradford

Barfly

Helen Kleeb

Phone Operator Rachel

Brett Parker

Security Guard

Ford Rainey

The President

Hal Torey

General

Fred Crane

Alpha Control Technician

Robert 'Big Buck' Maffei

The Giant Cyclops

William Bramley

Mr. Nobody

Françoise Ruggieri

Moela

Charles Dierkop

Horned Mutant

Walter Sande

Sheriff George Baxendale

Donald Losby

Davey Sims

Harry Harvey

Grover

Anne Dore

First Selectman

Michael Greene

Nubu

Harry Monty

Geoo

Maxine Gates

Fat Princess

Ken Mayer

Pleiades Pete

Bill Troy

Alien

Harry Raybould

Urso

June Foray

Gundemar (voice)

Jeff County

Gundemar

Larry Dean

Wooden Soldier

Bern Hoffman

Thor

Jim Boles

Smeek

Craig Duncan

Deek

Alan Hewitt

Lemnoc

Jim Mills

Saticon

Duke Fishman

Convict

Ben Frommer

Convict

Lars Hensen

Convict

Gil Perkins

Convixt

Mike Morelli

Convict

Pitt Herbert

Grover

Claire Wilcox

Stacy

Norman Leavitt

Charlie

Robert Pine

Craig

Grant Sullivan

Alien

Carol Williams

Alien

Tommy Farrell

Cyborg

Bart La Rue

Alien Machine (voice)

Kenya Coburn

Zaybo

Don Eitner

Sgt. Smith

Linda Gaye Scott

Aien Girl

Ralph Lee

Mechanical Man

Gary Tigerman

Oggo

Ronald Weber

Mort

Tom Allen

Inspector (uncredited)

Carroll Roebke

Tat

Eric Matthews

QZW

Richard Krisher

MXR

Corinna Tsopei

Princess Reyka

Alberto Monte

Chavo

Jim Gosa

Gilt Proto

Byron Morrow

General Squires

Gil Rogers

Bartholomew

Charles Horvath

Guard

Miriam Schiller

Miss Teutonium

James Millhollin

Willoughby