Otoboku: Maidens are Falling for Me!

Mizuho, a young boy who has recently lost his grandfather, strives to obey his last wish—graduate from Seio, a private female-only school. In order to complete this last wish, Mizuho disguises himself as a female with some help from his childhood friend, Mariya and another Seio student, the wise Shion. Mizuho eventually meets two younger girls, Yukari and Kana, whom she and Mariya must mentor. He also meets an old rival of Mariya’s—the traditional Takako. Mizuho’s journey is filled with many obstacles including using feminine language, adhering to feminine behaviors and even competing in an election to school office.

Synopsis from Anime News Network