Maison book girl, originally known as Book House Girl and sometimes abbreviated as BookGa (ブクガ), was a japanese alt-idol group formed in July 2014 and produced by Sakurai Kenta (サクライケンタ).
It consisted of 4 members : Koshoji Megumi (コショージメグミ ; former BiS member), Yagawa Aoi (矢川葵 ; Miss iD 2015 finalist), Inoue Yui (井上唯) and Wada Rin (和田輪).

In addition to their musical activities, the girls promoted fashion, art and street culture. They also often worked with fashion & graphic designers.

They held their first live performance at @JAM the Field vol.6 in November 2014. Their first 2 singles White and Black were released simultaneously in March 2015. Those were limited editions only on sale at live music venues. Their first album Bath Room was released in September 2015. Their third single summer continue was released in March 2016.

They were disbanded May 30, 2021 on "Solitude HOTEL at Maihama Amphitheater in Chiba.
After this performance, a paper with a mysterious link URL was distributed at the venue. The link read, "Maison book girl has been deleted." It was a page announcing the end of the group's activities. Read more on Last.fm. User-contributed text is available under the Creative Commons By-SA License; additional terms may apply.