Dizdar (Persian: دزدار, romanized: dizdār; Turkish: dizdar, kale muhafızı) was the title given in the Ottoman Empire to a castle warden or fortress commander, appointed to manage troops and keep the fortress in its role as a defence point.

The word is of Persian origin, meaning gatekeeper, watchman, guardsman or castellan. It spread to the west following the Ottoman conquest of the Balkans.

Dizdar commanded military unit in the fortress, but at the same time he was responsible for the settlement (village or town) under or around it as well, because the purpose of fortress was to defend the area.

As a commanding person, dizdar had his deputy, called chekhaya (Turkish: kâhya), and other subordinates (e.g. yasakci). His superiors were captain, sanjakbeg and other senior military officers.

In 1839 after the Tanzimat reforms, the Ottoman Empire abolished captaincies; the titles like captain and dizdar ceased to exist.