The (“The Stockholm Syndrome,” Series 12, Episode 24) aired May 16, 2019. It was the most-watched scripted series episode of the 2018–2019 TV season.
All 12 series are widely available:
The Big Bang Theory's finale, titled "The Stockholm Syndrome," aired on May 16, 2019, and was watched by over 18 million viewers, making it one of the most-watched series finales of all time. how many series of the big bang theory are there