Here are four roleplays I found that take place in a school or academy. There are probably more.
Harry Potter RP (Hogwarts) -
"Oɴ ᴛᴏ ᴛʜᴇ ᴘʟᴏᴛ! Iᴛ ɪs ʏᴇᴀʀs, ᴍᴀɴʏ, ᴍᴀɴʏ, ᴍᴀɴʏ ʏᴇᴀʀs... Mᴏʀᴇ ʟɪᴋᴇ
ɢᴇɴᴇʀᴀᴛɪᴏɴs (ᴡɪᴛʜ ᴀɴ 'S') ᴀғᴛᴇʀ ᴛʜᴇ Hᴏɢᴡᴀʀᴛs Cʟᴀss ᴛʜᴀᴛ
ᴇᴠᴇʀʏᴏɴᴇ ᴋɴᴇᴡ ᴀɴᴅ ʟᴏᴠᴇᴅ. Iɴ ғᴀᴄᴛ, ᴊᴜsᴛ sᴏ ᴛʜᴀᴛ ɴᴏ ᴏɴᴇ ᴄᴀɴ
ɢᴇᴛ ᴄᴏɴғᴜsᴇᴅ, ʟᴇᴛ's sᴀʏ ɪᴛ's sᴏᴍᴇᴡʜᴇʀᴇ ᴀʀᴏᴜɴᴅ ғɪᴠᴇ
ɢᴇɴᴇʀᴀᴛɪᴏɴs ᴀғᴛᴇʀ Hᴀʀʀʏ Pᴏᴛᴛᴇʀ ᴀɴᴅ ʜɪs ᴄʀᴇᴡ ʟᴇғᴛ ᴀɴᴅ
ɢʀᴇᴡ ᴜᴘ ᴀᴛ ʟᴇᴀsᴛ."... "ʙᴜᴛ ʀɪɢʜᴛ
ɴᴏᴡ ɪᴛ ɪs ᴊᴜsᴛ ᴀ ʏᴇᴀʀ ᴀᴛ Hᴏɢᴡᴀʀᴛs. I'D sᴀʏ ᴀ ɴᴏʀᴍᴀʟ ʏᴇᴀʀ, ʙᴜᴛ
ᴛʜᴇʀᴇ ɪs sᴇʟᴅᴏᴍ ᴀɴʏᴛʜɪɴɢ 'ɴᴏʀᴍᴀʟ' ᴀʙᴏᴜᴛ ᴛʜᴇ sᴄʜᴏᴏʟ."
Eureka Academy: First Semester (Science Fantasy) -
"At its core, EA is meant to be semi-freeform, which as I learned it means that while the overarching plot is in the GM's hands the pieces that form it are largely in the hands of the players." ... "You, the RPers, have the option of being either professors or students within the Academy." ... "[A teacher's] job is to teach the students so if you don't think you have the leadership skills or the people skills to do this, please do not be a teacher."
New Heights Academy (Miscellaneous) -
"[New Heights Academy] is the largest building in the town, standing at four stories high and is one of the most prestigious schools in the entire country. The school itself is a product of the U.K and Japan both deciding to create a school that would teach the culture and the language of both the countries." ... "What's most interesting about the school is how it goes all the way from kindergarten to high school, this is to promote an easygoing environment where the students would never be separated from their friends and the amount of stress and depression would stay at a low level."
Elkhorn Private Academy (Magic School, Jump In Roleplay) -
"Welcome to Elkhorn academy! Where there are over grown monsters and deadly tests! You'll think back on the person who first said that to you after you settle in. That is if you live. Elkhorn Private Academy is designed to help people who have either been born, cursed, or created a magical vessel within themselves. To do so we train our powers on each other in what are called Exceptionals Exams."