The Big Bang Theory is an American sitcom that first aired on CBS on September 24, 2007. It was created by Chuck Lorre and Bill Prady. The ninth season began on September 21, 2015. 242 episodes of the show have aired.
The show centers on five characters: roommates Leonard and Sheldon; best friends Howard and Raj; and Penny, an actress. The guys' nerdy, intelligent, asocial personalities are juxtaposed with the normality of Penny. Over the series, new main characters Bernadette and Amy have been introduced as girlfriends of Howard and Sheldon, respectively. Stuart, the owner of a comic book store is also a main character in some seasons. Leslie Winkle was briefly a main character.
See List of The Big Bang Theory characters for more information.