[1] Braithwaite's debut novel was originally published in Nigeria as an e-book with the title Thicker Than Water in 2017 before being released in the United States by Doubleday Books on 20 November 2018.

Her practicality and concern keep Ayoola from acting suspiciously about her “missing” boyfriend, such as by posting to social media when she should be mourning.

My Sister, the Serial Killer was described by Deadline as a "darkly comedic story, buzzed-about in publishing circles.

[9] The novel was longlisted for the 2019 Booker Prize and was the second-highest best-selling title on the list as of July 2019, with 13,052 units sold according to Nielsen BookScan.

[10] My Sister, the Serial Killer has been praised by The New York Times,[11][12] The Washington Post,[13] Marie Claire and authors Ayọ̀bámi Adébáyọ̀ and Edgar Cantero.