The song was written by the artists and the Broadway musical's original composer Jeff Richmond and original lyricist Nell Benjamin, alongside Ryan Tedder, Alexander 23, Billy Walsh, and Jasper Harris and was released on December 15, 2023, as the lead single for the film soundtrack.

The song was first announced on December 10, 2023 by Megan Thee Stallion in a clip via Reneé Rapp's Instagram account.

[3]A disco-funk inspired "disco-pop" song[4][5] and pop rap song[6] with themes of self-love and empowerment,[5] "Not My Fault" opens with dialogue sampled from the original 2004 film Mean Girls, in which Cady Heron yells at Janis Ian: "You know what?

[19] Reneé Rapp and Megan Thee Stallion performed the song for the first time on Saturday Night Live on January 21, 2024.

The performance was introduced by Rachel McAdams, who played Regina George in the original Mean Girls film.