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 (11 eps)
Joshua Malina
President Siebert (9 eps)
Rati Gupta
Anu (9 eps)
Lauren Lapkus
Denise (6 eps)
Brian Posehn
Bert Kibbler (5 eps)
Pamela Adlon
Halley Wolowitz (voice) (3 eps)
Kal Penn
Kevin Campbell (3 eps)
Sean Astin
Greg Pemberton (3 eps)
Christine Baranski
Beverly Hofstadter (3 eps)
Kathy Bates
Mrs. Fowler (2 eps)
Teller
Larry Fowler (2 eps)
Keith Carradine
Wyatt Teller (2 eps)
Chasty Ballesteros
Karen (2 eps)
David Theune
Dr. Graybel (2 eps)
Brian Thomas Smith
Zack Johnson (2 eps)
Lindsey Kraft
Marissa Johnson (2 eps)
Bill Nye
Bill Nye (1 eps)
Neil deGrasse Tyson
Neil deGrasse Tyson (1 eps)
Giovanni Bejarano
Bellman (1 eps)
Ciara Renée
Sunny Morrow (1 eps)
Andy Taylor Kim
Tour Guide (1 eps)
Luis Aldana
Greg (1 eps)
Kikey Castillo
Leslie (1 eps)
Matt Knudsen
Waiter (1 eps)
Robert Wu
Tam Nguyen (1 eps)
Eddie Shin
Dr. Park (1 eps)
Alison Martin
Andrea (1 eps)
Hermie Castillo
Colin (1 eps)
Iain Armitage
Sheldon Cooper (1 eps)
Lance Barber
George Cooper (1 eps)
Montana Jordan
Georgie Cooper (1 eps)
Kurt Scholler
Judge (1 eps)
Jerry O'Connell
Georgie Cooper (1 eps)
Maribeth Monroe
Dr. Lee (1 eps)
Hira Ambrosino
Cynthia (1 eps)
Hugh Kennedy
Chad (1 eps)
Keili Lefkovitz
Brenda (1 eps)
Andy Daly
Nathan (1 eps)
Joel McCrary
Andy (voice) (1 eps)
Eric Nenninger
Neil (1 eps)
Wil Wheaton
Wil Wheaton (1 eps)
Joe Manganiello
Joe Manganiello (1 eps)
Kareem Abdul-Jabbar
Kareem Abdul-Jabbar (1 eps)
William Shatner
William Shatner (1 eps)
Jason Kravits
Danny (1 eps)
Ben Rauch
Darren (1 eps)
Brooke Dillman
Bebe (1 eps)
Regina King
Janine Davis (1 eps)
Doreen Calderon
Woman #1 (1 eps)
Sarah Eagen
Woman #2 (1 eps)
Claudia Choi
Woman #3 (1 eps)
Tiffany Commons
Woman #4 (1 eps)
Krishna Smitha
Woman #5 (1 eps)
Angela Lin
Maritza (1 eps)
Elijah Isaiah Cook
Terry (1 eps)
Todd Giebenhain
Mitch (1 eps)
Blair Hickey
Reporter #2 (1 eps)
Dinora Walcott
Reporter #1 (1 eps)
Rodney J. Hobbs
Reporter #3 (1 eps)
Sarah Michelle Gellar
Sarah Michelle Gellar (1 eps)
Bob Newhart
Arthur Jeffries (1 eps)
Kevin Smith
Kevin Smith (1 eps)
Caleb Pierce
Jess (1 eps)
Shay Ali
Greg (1 eps)
Chip Chinery
Bob (1 eps)
Minerva García
Linda (voice) (1 eps)
Hilda Boulware
Woman (1 eps)
Andre Boyer
Kwame (1 eps)
Ellen DeGeneres
Ellen DeGeneres (1 eps)
George F. Smoot
George F. Smoot (1 eps)
Frances H. Arnold
Frances H. Arnold (1 eps)
Kip Thorne
Kip Thorne (1 eps)
Susan Leslie
Woman #6 (1 eps)
Cassidey Fralin
Woman #7 (1 eps)
Riley Go
Woman #8 (1 eps)
Cleo Fraser
Little Girl (1 eps)
Thomas Albany
Carl XVI Gustaf of Sweden (1 eps)
Sailah Nicol
Halley Wolowitz (1 eps)
Nate Ash
Michael Wolowitz (1 eps)
Ulf Bjorlin
Announcer (1 eps)
Major Mike
Daniel Westling (1 eps)
Jeanelle Marie Cruz
Bike Messenger (uncredited) (1 eps)