Hanazakari no Kimitachi e

Japanese-American track-and-field star Mizuki has gotten herself to transfer to a high school in Japan...but not just any school! To be close to her idol, high jumper Izumi Sano, she's going to an all-guys' high school...and disguising herself as a boy! But as fate would have it, they're more than classmates...they're roommates! Now, Mizuki must keep her secret in the classroom, the locker room, and her own bedroom. And her classmates--and the school nurse--must cope with a new transfer student who may make them question their own orientation...
(Source: Viz Media)