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 (8 eps)
Carol Ann Susi
Debbie Wolowitz (voice) (4 eps)
Margo Harshman
Alex Jensen (4 eps)
Pasha D. Lychnikoff
Dimitri (4 eps)
Michael J. Massimino
Michael J. Massimino (2 eps)
Regina King
Janine Davis (2 eps)
Ian Scott Rudolph
Captain Sweatpants (uncredited) (2 eps)
LeVar Burton
LeVar Burton (1 eps)
Dakin Matthews
Santa Claus (1 eps)
Troy Winbush
Paramedic (1 eps)
Casey Sander
Mike Rostenkowski (1 eps)
David Trice
Waiter (1 eps)
Josh Brener
Dale (1 eps)
Ryan Cartwright
Cole (1 eps)
William Stanford Davis
Dry Cleaner (1 eps)
Buzz Aldrin
Self (1 eps)
Meagen Fay
Mrs. Rostenkowski (1 eps)
Matt Battaglia
Officer Reynolds (1 eps)
Janelle Marra
Claire (1 eps)
Piper Mackenzie Harris
Girl #1 (1 eps)
Riccardo LeBron
Tom (1 eps)
Angela Sargeant
Lana (1 eps)
Ken Lerner
Dr. Schneider (1 eps)
Craig Gellis
Car Thief #1 (1 eps)
Diamond White
Girl #2 (1 eps)
Jan Hoag
Lillian (1 eps)
Frank Alvarez
Car Thief #2 (1 eps)
Briana Cuoco
Gretchen (1 eps)
Dawson Fletcher
Justin (1 eps)
John Mendoza
Chauffeur (1 eps)
Rick Gifford
Guy (1 eps)
Wil Wheaton
Wil Wheaton (1 eps)
Bob Newhart
Arthur Jeffries (1 eps)
Brian Posehn
Bert Kibbler (1 eps)
Stephane Nicoli
Guy at the Movies (uncredited) (1 eps)
Howie Mandel
Howie Mandel (1 eps)
Jesse Heiman
Comic Book Store Customer (uncredited) (1 eps)
Seaonna Chanadet
Eye Rolling Girl Student (uncredited) (1 eps)
Stephen Hawking
Stephen Hawking (1 eps)
Bryan Stamp
Library Graduate Student (uncredited) (1 eps)