OMG! There are so many to pick from. Its like 1/3 of all the yaoi manga.
These are 2 of my faves.
http://www.mangago.zone/read-manga/adam_no_junjou/
http://www.mangago.zone/read-manga/bokura_no_unsei/
But there are 39 pages of anything highschool related.
http://www.mangago.zone/r/l_search/?page=1&name=high+school+yaoi
maybe (some yaoi some shonen ai) - Kanemochi-kun To Binbou-kun, Udagawachou De Mattete Yo, Twinkle, Uchi no Ouji Irimasen ka, Lily Colored Lovers, Wild and Strawberry, Tender Love, Uwasa no Ouji-sama, Little Butterfly, Seven Days, Count
Jenketsu drop
Wild And Strawberry
Otona Keikenchi
Kimi Note
Twinkle
A Spectrum of Emotions (Kanjou Spectrum - Yoneda Kou)
Kawaii Akuma
Star-like Words
Gosan no Heart
Seven Days
so many ... =)
Uchi no ouji irimasen
sono koi ni wa wake ga aru
slow starter
walking with you
I love this one its cute with good plot
http://www.mangago.zone/read-manga/count/
http://www.mangago.zone/read-manga/kono_ore_ga_omae_nanka_suki_na_wakenai/
http://www.mangago.zone/read-manga/rutta_to_kodama/
http://www.mangago.zone/read-manga/hatsuai/
http://www.mangago.zone/read-manga/dounimo_nannai_soushi_souai/
http://www.mangago.zone/read-manga/i_want_to_be_naughty/ (the first two couples from the warui series)
http://www.mangago.zone/read-manga/hanayome_kun/
http://www.mangago.zone/read-manga/karada_meate_de_warui_ka/
http://www.mangago.zone/read-manga/elektel_delusion/
http://www.mangago.zone/read-manga/koi_nante_shinai/
http://www.mangago.zone/read-manga/megane_goshi_no_sora_wa/
http://www.mangago.zone/read-manga/twinkle/
http://www.mangago.zone/read-manga/dash/
blue sky complex, seven days, rutta to kodama, sekai wa kimi de mawatteru, udagawachou de mattete yo
Read the Warui series. It's really good. Here is the list in order.
1. Warui Koto Shitai
2. Warui Ko Demo Ii?
3. Kirai ja Nai Kedo
4. Warui Yatsu Demo Ii
5. Koi ja Nai Kedo
- Warui Koto Bakkashite Gomennasai
6. Mujihi na Otoko
7. Warui Koibito ja Dame?
8. Kare ja Nai Kedo
9. Mujihi na Anata
10. Sunao ja Nai Kedo
11. Warui Ouji Demo Suki
12. Mujihi na Karada
- Seiaku Ookami ga Koi o Shitarashii
sweet highschool yaois?