My Stepmom's Daughter Is My Ex

is a Japanese romantic comedy light novel series written by Kyōsuke Kamishiro and illustrated by Takayaki. The series began serialization on the online novel website Kakuyomu in August 2017, with a print version beginning publication under Kadokawa Shoten's Kadokawa Sneaker Bunko imprint in December 2018. The light novel is licensed digitally in North America by J-Novel Club. A manga adaptation by Rei Kusakabe began serialization online by Fujimi Shobo via Niconico Seiga website as part of the Dra Dra Sharp and Dra Dra Flat brands in April 2019. An anime television series adaptation produced by Project No.9 aired from July to September 2022.