CBS and Warner Bros. Television have agreed a two-season renewal deal for The Big Bang Theory, taking the show through to its twelfth season Until now, The Big Bang Theory was not contracted past its current tenth season, though as the #1 scripted series in viewers and key demos a renewal deal was expected. 

The forty-eight episode deal will see The Big Bang Theory return for its eleventh season this fall and a twelfth season in 2018/19. Whether The Big Bang Theory's twelfth year will be its last has not been decided yet.

The Big Bang Theory's renewal follows the recent series order for a The Big Bang Theory spin-off, Young Sheldon, which will focus on a nine-year-old Sheldon growing up in Texas. The single-camera comedy is being produced by TBBT co-creator Chuck Lorre and showrunner Steven Molaro. Jim Parsons will be providing narration as the adult Sheldon.

The Big Bang Theory's five original cast members are already signed up to return with Mayim Bialik and Melissa Rauch expected to sign deals soon. According to press reports, the five original stars took a paycut to free up money for Bialik and Rauch, who both joined the show in its fourth season, and who have been on lower pay cycles.

The Big Bang Theory was previously renewed for three seasons back in 2014 which took the show through to its current tenth season. The tenth season of The Big Bang Theory continues next Thursday, March 30 with "The Collaboration Fluctuation".