Mitsudomoe (みつどもえ, "Three-Way Struggle") is a Japanese gag manga series by manga artist Norio Sakurai about the adventures of the Marui triplets in sixth grade and their newly hired teacher Satoshi Yabe as he deals with his new class. The series was first serialized in Weekly Shōnen Champion in 2006 before moving to Bessatsu Shōnen Champion in 2012. Akita Shoten has published the series in both of their magazines. The series follows the everyday life of three sisters, their classmates, and their unfortunate teacher.

The series has been collected into nineteen tankōbon manga volumes the first of which was released on January 9, 2006. In July 2010, the manga was adapted into an anime series that ran for 13 weeks first airing on Chubu-Nippon Broadcasting. A second series called Mitsudomoe Zōryōchū! (みつどもえ 増量中！, "Mitsudomoe: Increasing!") was made the following year that aired between January 9, 2011 and February 28, 2011. Although the series has not been licensed for release in North America, it has been simulcast by Crunchyroll which subbed the series. The first anime adaptation has received mixed reviews with most saying that while the humor will creep some out, others will enjoy it.