Happy☆Lesson

Happy Lesson (ハッピー・レッスン) is a Japanese comedy manga, written by Mutsumi Sasaki and illustrated by Shinnosuke Mori, serialized in Dengeki G's Magazine from April 1999 to September 2002. It was adapted into a five-part OVA series in 2001; a thirteen-episode animated TV series in 2002; a sequel TV series, called Happy Lesson Advance, in 2003; and a second OVA series, Happy Lesson: The Final, in 2004.

Plot
Five girls and one guy under one roof. An orphaned Chitose Hitotose does his best to live on his own in his deceased parents' house, but not until it affects his grades. Noticing this, five teachers plane to live with Chitose in his house, while each having an unusual plan to become mother figures in an effort to make him a productive student.