放課後ティータイム (Houkago Tea Time, or HTT, literally “After School Tea Time”) is a girl band from the anime series, K-On! (“K-On” being pronounced as 軽音 keion, which means “light music” in Japanese). The songs are performed by their voice actresses with the help of professional musicians. The group originally debuted as 桜高軽音部 (Sakuragaoka High School Light Music Club), a four-member group, before the addition of underclassman Azusa Nakano, thus forming the group into a five-member band with a name-change.

The band members in the show are:
- Yui Hirasawa: guitarist, vocalist and songwriter.
- Mio Akiyama: bassist, vocalist and songwriter.
- Ritsu Tainaka: drums and leader.
- Tsumugi Kotobuki: keyboard and composer.
- Azusa Nakano: rhythm guitarist.