The Vilayet of Manastir was a first-level administrative division (vilayet) of the Ottoman Empire, created in 1874, dissolved in 1877 and re-established in 1879. The vilayet was occupied during the First Balkan War in 1912 and divided between the Kingdom of Greece and the Kingdom of Serbia, with some parts later becoming part of the newly established Principality of Albania.

A vilayet, also known by various other names, was a first-order administrative division of the later Ottoman Empire. It was introduced in the Vilayet Law of 21 January 1867, part of the Tanzimat reform movement initiated by the Ottoman Reform Edict of 1856. The Danube Vilayet had been specially formed in 1864 as an experiment under the leading reformer Midhat Pasha. The Vilayet Law expanded its use, but it was not until 1884 that it was applied to all of the empire's provinces. Writing for the Encyclopaedia Britannica in 1911, Vincent Henry Penalver Caillard claimed that the reform had intended to provide the provinces with greater amounts of local self-government but in fact had the effect of centralizing more power with the sultan and local Muslims at the expense of other communities.