My all-time fav school-involved dramas are:
1. Playful Kiss - they both attend the same sec sch then move on to the same uni as well! The romance is pretty cute and the show is very enjoyable to watch :D It's the korean version of It Started With A Kiss. I didn't watch the taiwan version but I heard it's good. Still, give playful kiss a shot!
2. Heartstrings - in a university setting, though mostly focused on the music (modern & traditional) majors. Very fun to watch, loved the whole cast, all the students, the teachers, the leads, the 2 bands, and an incredible ost! Be sure to give this a shot! ^^
3. To The Beautiful You - It's a very cute and fun-loving drama, set in an all-boys school (so the girl cross-dressed as a boy). The show is more of a 'secondary school' or 'high school' setting, rather than university. But the boys and teachers are all really fun to watch!
Hana Kimi - The taiwanese version, has its own charm that the korean version lacked, but at the same time lacked some charm that the korean one had >< I enjoyed both! Though the korean one definitely has a better soundtrack (as expected of kdramas ;)
4. God Of Study - someone aboved also suggested this. This is in a high school setting, and as compared to the previous 3 i mentioned, this drama has much more depth. It is not a cheery and bright as the first 3, but it's much more heartfelt and realistic than them. It's bout 5 students who score poorly, but through the help of each other and their teachers, they grow together,overcoming their differences, their conflicts, their family backgrounds, their own personal problems, and at the end of the day, become the victor in their own lives! This drama made me cry a lot, as compared to the other 3 (ok fine maybe on par with Playful Kiss?) but it's a very beautiful and encouraging show. I recommend it to anyone who is still schooling especially! Adults will love it too though ;)