Under17 (アンダーセブンティーン) was a popular Japanese duo that wrote and performed many songs that are featured in anime and video games.

The lead singer, Momoi Haruko, is well known for her unique vocals and catchy lyrics.

Some of the anime series where Under17 songs have been featured are DearS, Kujibiki Unbalance, Tenbatsu Angel Rabbie, Mouse, and Popotan.

This group has released several adult videogames' opening songs.

On September 27, 2004, it was announced that Under17 would break up, with Momoi Haruko and Koike Masaya going separate ways due to creative differences.

The band reunited for one song on August 31, 2008 during the Animelo Summer Live.

(Source: AniDB)