Johnny Galecki
Leonard Hofstadter (24 eps)
Jim Parsons
Sheldon Cooper (24 eps)
Kaley Cuoco
Penny (24 eps)
Simon Helberg
Howard Wolowitz (24 eps)
Kunal Nayyar
Rajesh Koothrappali (24 eps)
Melissa Rauch
Bernadette Rostenkowski (24 eps)
Mayim Bialik
Amy Farrah Fowler (24 eps)
Kevin Sussman
Stuart Bloom (7 eps)
Stephen Root
Dan (2 eps)
Carol Ann Susi
Debbie Wolowitz (voice) (2 eps)
Billy Bob Thornton
Oliver Lorvis (1 eps)
Kara Luiz
Jeanie (1 eps)
LeVar Burton
LeVar Burton (1 eps)
Annie O'Donnell
Mrs. Lorvis (voice) (1 eps)
Dakin Matthews
Santa Claus (1 eps)
Michael Reetz
Photographer (1 eps)
Noel De Souza
Older Indian Man (1 eps)
Ed Lieberman
Man (1 eps)
Jim Meskimen
Doctor (voice) (1 eps)
Nathan Fillion
Nathan Fillion (1 eps)
Angela Relucio
Hostess (1 eps)
Stephanie Escajeda
Cindy (1 eps)
Molly Morgan
Hostess (1 eps)
Max Adler
Zombie (1 eps)
Tate Ellington
Mitchell (1 eps)
Michael Dempsey
Security Guard (1 eps)
Mark Barrett
Security Guard #2 (voice) (1 eps)
Matt Bennett
Josh Wolowitz (1 eps)
Rena Strober
Caller (voice) (1 eps)
Sara Erikson
Gwen (1 eps)
Kelli Goss
Chelsea (1 eps)
Phoebe Neidhardt
Casting Assistant (1 eps)
Jeff Jingle
Alien (voice) (1 eps)
Mark Maitre
Alien #2 (voice) (1 eps)
Max Mittelman
Tech Support (voice) (1 eps)
Katherine Von Till
Tech Support Recording (voice) (1 eps)
Bruce Holman
Airport Pedestrian (1 eps)
Michael J. Massimino
Michael J. Massimino (1 eps)
Paul Willson
Professor Sharpe (1 eps)
Wil Wheaton
Wil Wheaton (1 eps)
Regina King
Janine Davis (1 eps)
Kevin Smith
Kevin Smith (1 eps)
Stephen Hawking
Stephen Hawking (1 eps)
David Barrera
Officer Hernandez (1 eps)
Anil Margsahayam
Man (1 eps)
Tonja Kahlens
Woman (1 eps)
Robert Noble
Older Gentleman (1 eps)
Malcolm Foster Smith
Roy (1 eps)
Michael Araujo
Stadium Announcer (voice) (1 eps)
Christine Baranski
Beverly Hofstadter (1 eps)