Gregory Tsamblak or Grigorij Camblak (Bulgarian: Григорий Цамблак; (c. 1365–1420) was a Bulgarian writer and cleric who was the metropolitan of Kiev between 1413 and 1420. A Bulgarian noble, Tsamblak lived and worked Bulgaria, but also in Medieval Serbia and Kyivan Rus and indebted these two countries to himself through his literary works, which represent a heritage of their national literatures, particularly the style of Old Serbian Vita made popular in the monasteries of the 12th century.