In general, all students from countries outside of TURKEY need to have a residence permit to study in Turkey if they are planning on staying for more than three months.
International students will need to check carefully whether they need a visa to enter Turkey. A Visa is a document necessary for entering the country and must be applied for prior to departure. It is a sticker in your passport issued by a Turkish Embassy or Consulate.
The Difference between residence permit and Visa ?
A visa is not the same as a residence permit. A residence permit is a document necessary for staying in the country and should be applied for after arrival.
All international students, regardless of their status, must register and obtain a Residence Permit (Ikamet Tezkeresi) from the Istanbul Provincial Immigration Administration Office within 10 days of entering Turkey. You can be required at any time to show your Residence Permit.