The eleventh season of the American television sitcom The Big Bang Theory premiered on CBS on Monday, September 25, 2017. It returned to its regular Thursday time slot on November 2, 2017, after Thursday Night Football on CBS ended.

Answer this question based on the passage: when is the big bang theory season 11 coming out? Okie... think carefully first, then make a decision:
To answer the above question, the relevant sentence is: The eleventh season of the American television sitcom The Big Bang Theory premiered on CBS on Monday, September 25, 2017. So, the answer is Monday , September 25 , 2017.