In which city is The Big Bang Theory set?

The Big Bang Theory is set in Pasadena, California. The fictional homes, workplaces, and social lives of the main characters are centered in and around the Los Angeles-area city.

Leonard Hofstadter and Sheldon Cooper share an apartment in Pasadena, directly across the hall from Penny. Their workplace is the California Institute of Technology, or Caltech, which is also located in Pasadena. Raj Koothrappali works there as an astrophysicist, while Howard Wolowitz is an aerospace engineer associated with the same scientific circle.

The show is often mistaken as being set in Los Angeles because Pasadena is part of the broader Los Angeles metropolitan area, and many scenes depict Southern California life. Pasadena, however, is its own city with a distinct identity and is specifically named as the show's setting. New York and San Francisco are not the primary locations, although characters occasionally travel elsewhere.

The series used studio sets for the apartment interiors and other recurring locations, while Pasadena's real-world identity helped give the story a recognizable Southern California backdrop.