You are welcome with your UAV in Turkey
Maximum take-off weight: 4 kilo
Maximum hight: 120 meters / 393 ft
Maximum horizontal distance: 750 meter (2,460 ft).
Minimum Age: -
Insurance: Not known
Distance Airports / Heliports: 15 km / 9.5 mi.
Night flights: Prohibited
Prohibited: flying over crowds, military, governments buildings, bosporus, concerts, ships, people, animals,
UPDATE FEBRUARI 2019:
It's posible to register your UAV, do it HERE.
But, it is not tested yet, so please let us know if it works.
Some people say it's only for Commercial use.
UPDATE JANUARI 2019
situation is not changed, UAV are still confiscated at the border.
UPDATE DECEMBER 2018:
Leave your UAV at home, UAVs are confiscated at the borders
Useful link: States Airport Administration of Turkey (SAMA)
Contact information: firstname.lastname@example.org / +90 0312 204 20 00