List of The Big Bang Theory episodes

The Big Bang Theory is an American comedy television series created and executively produced by Chuck Lorre and Bill Prady. Like the name of the series itself (with the exception of the first episode "Pilot"), episode titles of The Big Bang Theory always start with "The" and resemble the name of a scientific principle, theory or experiment, whimsically referencing a plot point or quirk that is stated in that episode.

In March 2014, the show was renewed for three more years through a tenth season, which premiered on September 19, 2016. As of March 9, 2017^[update], 225 episodes of The Big Bang Theory have aired. In March 2017, CBS announced that the series was renewed for two more years, leading the show to a total of 12 seasons. There was also an unaired pilot which CBS did not broadcast.

The original pilot, which CBS passed on, featured Amanda Walsh as Katie instead of Kaley Cuoco as Penny and had a darker tone.

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