At which university do Leonard and Sheldon work in The Big Bang Theory? Leonard and Sheldon work at Caltech, the California Institute of Technology.
The Pasadena-based institution is the professional home of much of the show's scientific world. Sheldon is a theoretical physicist, while Leonard is an experimental physicist. Their friends Howard Wolowitz and Raj Koothrappali also work there, creating the shared workplace that connects the central characters beyond their apartment and social gatherings.
Caltech is not technically named a university in its official title; it is a private research institute commonly known as the California Institute of Technology. In everyday quiz wording, however, “Caltech” is the canonical answer to where Leonard and Sheldon work. The real institution is renowned for science and engineering and is located in Pasadena, California.
A common mix-up comes from the characters' educational backgrounds. Leonard has ties to Princeton, Howard studied engineering at MIT, and Raj studied at Cambridge. Those schools are associated with the characters, but their workplace in the series is Caltech.