Oku-sama wa Joshi Kōsei (おくさまは女子高生; lit. 'My Wife is a High School Girl') is a Japanese manga series written and illustrated by Hiyoko Kobayashi . It started in the supplementary edition of Shueisha's seinen manga magazine Weekly Young Jump, Young Jump Zōkan Mankaku in January 2001, and transferred to the main magazine in October of the same year, concluding in March 2007. Its chapters were collected in 13 volumes. The series centers on a couple whose age difference makes it difficult for them to further their relationship, as one is a high school girl and the other is her physics teacher.

A video game based on the series was released for the PlayStation 2 and later the Dreamcast as a "Director's Edition", both in 2002. A 13-episode anime television series adaptation, produced by Avex Entertainment and Madhouse, was broadcast from July to September 2005, with each episode composed of two mini-episodes.

Asami Onohara (小野原 麻美, Onohara Asami) is a 17-year-old high-school student (voiced by Ayako Kawasumi) with a secret which has not been revealed to anyone: she is already married. Her husband, Kyosuke Ichimaru (市丸 恭介, Ichimaru Kyōsuke) (voiced by Mitsuaki Madono), is a physics teacher in the same high school as her. However, even though they are officially a married couple, Asami's father forbids them to have any sexual contact until after Asami has graduated. Asami has to hide the fact that she is married to Kyosuke while trying desperately to further their relationship, and it does not help when there are so many obstacles from her father and other third parties.