Tomo-chan wa Onnanoko!

Tomo-chan wa Onnanoko! (トモちゃんは女の子!, lit. "Tomo-chan Is a Girl!") is a manga series by Fumita Yanagida. It is serialized in twi4.

Plot
Tomo Aizawa was able to successfully confess to her crush Juunichirou Kubota. There is only one problem: he just sees her as his buddy. He thought that she was a boy until they went to middle school together because her grade school was in a different school district.