Isaac Kontostephanos (Greek: Ἰσαάκ Κοντοστέφανος) was a Byzantine admiral during the reign of Emperor Alexios I Komnenos (r. 1081–1118), marked by his incompetence in the wars against the Normans.
Although his forces could have taken the city by storm, Kontostephanos allowed himself to be involved in negotiations with Emma, which she dragged on until Norman reinforcements arrived.
Defeated in battle by the newly arrived Norman troops, Kontostephanos and his fleet were forced to withdraw to the Albanian coast.
[5] After Bohemond's successful landing, the emperor charged Kontostephanos with intercepting the Norman supply convoys, but here too he failed.
After receiving letters from Landulf detailing Kontostephanos's incompetence, Alexios finally dismissed him in summer 1108 and replaced him with Marianos Maurokatakalon.