This is a list of The Big Bang Theory guest stars. Most "played" themselves. The episodes in which they appeared are followed by the season in brackets.
The Big Bang Theory is an American television sitcom created by Chuck Lorre and Bill Prady, both of whom served as executive producers and head writers on the series, along with Steven Molaro. It aired on CBS from September 24, 2007, to May 16, 2019, running for 12 seasons and 279 episodes.
Leonard Leakey Hofstadter, Ph.D., is a fictional character portrayed by Johnny Galecki and one of the main protagonists in the CBS sitcom, The Big Bang Theory. Leonard is an experimental physicist who shares an apartment with his colleague and best friend, Dr. Sheldon Cooper. For his portrayal, Galecki was nominated for a Primetime Emmy Award and a Golden Globe Award in 2011.
Sheldon Lee Cooper, Ph.D., Sc.D., is a fictional character and one of the main protagonists in the CBS television series The Big Bang Theory and its spinoff series Young Sheldon, portrayed by actors Jim Parsons and Iain Armitage respectively. For his portrayal, Parsons won four Primetime Emmy Awards, a Golden Globe Award, a TCA Award, and two Critics' Choice Television Awards. The character's childhood is the focus of Young Sheldon, in which he grows up in East Texas with his family Missy Cooper, George Cooper Sr., George Cooper Jr., Mary Cooper and his MeeMaw as a child prodigy.
Howard Joel Wolowitz is a fictional character on the CBS television series The Big Bang Theory, portrayed by actor Simon Helberg. Among the four main male characters in the show, Howard is distinctive for being an engineer—rather than a physicist—and lacking a PhD. He is named after and based on a computer programmer known by the show's co-creator; Bill Prady. Howard is the only starring character who has been to the International Space Station. Along with Sheldon Cooper, Leonard Hofstadter, and Raj Koothrappali, Howard is part of the central cast of the show.
Rajesh "Raj" Ramayan Koothrappali, Ph.D. is a fictional character on the CBS television series The Big Bang Theory, portrayed by British actor Kunal Nayyar. He is one of four main male characters in the show, alongside Sheldon Cooper, Leonard Hofstadter and Howard Wolowitz to appear in every episode of The Big Bang Theory. Raj is based on a computer programmer that the show's co-creator, Bill Prady, knew when he was a programmer.
Penelope "Penny" Hofstadter is a fictional character from the American CBS sitcom The Big Bang Theory, portrayed by actress Kaley Cuoco. She is the primary female character in the series, befriending her neighbors Sheldon Cooper and Leonard Hofstadter, two physicists employed at the California Institute of Technology (Caltech).
David Paul Saltzberg is an experimental particle physicist and a professor at the University of California, Los Angeles, who is known for his science consultancy work on various television shows and films, such as The Big Bang Theory, Manhattan and Oppenheimer. His research involves high-energy collider physics and the radio detection of cosmic neutrinos, and in 2018, he was inducted as a fellow of the American Physical Society.
Amy Farrah Fowler, Ph.D., is a fictional character in the CBS television series The Big Bang Theory, portrayed by Mayim Bialik. Amy is a neuroscientist who is the love interest of Sheldon Cooper and subsequent wife in the series. She has a PhD in neurobiology, with a research focus on addiction in primates and invertebrates, occasionally mentioning such experiments as getting a capuchin monkey addicted to cigarettes or getting a starfish addicted to cocaine. Amy goes on to win the Nobel Prize in Physics alongside her husband.
The fifth season of the American television sitcom The Big Bang Theory aired on CBS from September 22, 2011 to May 10, 2012. The season includes the 100th episode of the series.
"The Hofstadter Insufficiency" is the first episode of the seventh season of The Big Bang Theory and the 136th episode in total. It aired on September 26, 2013, on CBS.
"The Hawking Excitation" is the 21st episode of the fifth season of The Big Bang Theory that first aired on CBS on April 5, 2012. It is the 108th episode overall. After learning that Stephen Hawking is coming to lecture at Caltech, Howard is hired to maintain his wheelchair equipment. When Sheldon discovers this, he is desperate to meet Hawking. Howard says he can, but only if he completes a humiliating series of tasks.
"The Convention Conundrum" is the 14th episode of the seventh season of the U.S. sitcom The Big Bang Theory and the 149th episode of the show overall. It first aired on CBS on January 30, 2014.
"The Hot Troll Deviation" is the fourth episode of the fourth season of the US sitcom The Big Bang Theory and the 67th episode of the show overall. It first aired on CBS on October 14, 2010. In the episode, Howard and Bernadette go on a date following their breakup a few months prior. Sheldon and Raj engage in a series of "tit for tat" exchanges when working together. The title refers to Howard's virtual affair with a troll on World of Warcraft.
The ninth season of the American television sitcom The Big Bang Theory aired on CBS from September 21, 2015 to May 12, 2016. The series returned to its regular Thursday night time slot on November 5, 2015 beginning with the season's seventh episode. On March 12, 2014, The Big Bang Theory was renewed for an additional three years, extending it through the 2016–17 television season for a total of ten seasons. Laura Spencer was promoted to the main cast during this season after being a recurring cast member for two seasons.
Young Sheldon is an American coming-of-age sitcom television series created by Chuck Lorre and Steven Molaro that aired on CBS from September 25, 2017, to May 16, 2024. The series is a spin-off prequel to The Big Bang Theory that takes place during the late 1980s and early-to-mid-1990s, and follows child prodigy Sheldon Cooper as he grows up with his family in East Texas. Iain Armitage stars as Sheldon, alongside Zoe Perry, Lance Barber, Montana Jordan, Raegan Revord, and Annie Potts. Jim Parsons, who portrayed the adult Sheldon Cooper on The Big Bang Theory, narrated the series and served as an executive producer.
"The Bath Item Gift Hypothesis" is an episode of the American comedy television series The Big Bang Theory. It first aired on CBS in the United States on December 15, 2008. It is the eleventh episode of the second season of the series and the twenty ninth episode overall.
"The Conjugal Configuration" is the first episode of the twelfth and final season of the American television sitcom The Big Bang Theory, and the 256th episode of the series overall. The episode first aired on CBS on September 24, 2018.
"The D&D Vortex" is the sixteenth episode of the twelfth and final season, and 271st episode overall of The Big Bang Theory. It first aired on CBS on February 21, 2019. The episode features several guests playing themselves, including William Shatner.
Georgie & Mandy's First Marriage is an upcoming American sitcom television series created by Chuck Lorre, Steven Molaro, and Steve Holland. The series is set to premiere on October 17, 2024 on CBS.