Dejan Manjak (Serbian Cyrillic: Дејан Мањак, fl.

1333) was a nobleman in the service of Serbian King Stefan Dušan, only mentioned in a charter dated January 22, 1333,[1] in which Stefan Dušan officially sold Ston and Prevlaka to the Republic of Venice.

[2][3] Based on the order in which the witnesses appear, vojvoda Dejan was of lower rank than stavilac Miloš.

[2][5] According to two fresco compositions dated between 1332 and 1337 in the Kučevište Monastery, in the narthex, on the northern and southern wall, Dejan had a wife, Vladislava, and two sons, Jovan and Dmitar.

Dejan is depicted on the southern wall with his wife standing next to Stefan Dušan and his wife Jelena.