The twelfth and final season of the American television sitcom The Big Bang Theory premiered on CBS on September 24, 2018.[1][2] The series returned to its regular Thursday time slot on September 27, 2018.

In March 2017, CBS renewed the series for two additional seasons, bringing its total to twelve, and running through the 2018–19 television season.[3] On August 22, 2018, CBS and Warner Bros. Television officially announced that the twelfth season would be the series' last. This stems from Jim Parsons' decision to leave the series at the end of the season if the show were to be renewed for a thirteenth season.[1][4][5]