Boku wa Imōto ni Koi o Suru (僕は妹に恋をする, lit. I'm in love with my sister; abbreviated to BokuImo) is a Japanese manga series written and illustrated by Kotomi Aoki. Originally serialized in the magazine Shōjo Comic, its chapters were published in ten tankōbon volumes by Shogakukan from May 2003 to August 2005. The series focuses on fraternal twins Yori and Iku, who fall in love with one another despite being siblings.

A ten volume spin-off series focusing on Yori's upperclassmen Takuma Kakinouchi and his childhood sweetheart Mayu Taneda was serialized in Shōjo Comic from December 2005 through August 2008. It is called Boku no Hatsukoi o Kimi ni Sasagu (abbreviated to BokuKimi) and means "I Give My First Love to You". The manga series was adapted into a one-episode original video animation (OVA) that was released in May 2005 and a live-action film starring Jun Matsumoto and Nana Eikura that premiered in Japan on January 20, 2007.

As of May 2006, the manga had over 2.5 million copies in circulation. In 2008, Boku no Hatsukoi o Kimi ni Sasagu won the 53rd Shogakukan Manga Award for the shōjo category.