Bitlis Vilayet ( Bit'lisi vilayet' , Ottoman Turkish: ولایت بتليس) was a first-level administrative division (vilayet) of the Ottoman Empire. Before the Russo-Turkish War (1877–1878) it had been part of the Erzurum Vilayet, it was then made a separate vilayet by the Sublime Porte. It was one of the six Armenian vilayets of the Empire.
At the beginning of the 20th century, Bitlis Vilayet reportedly had an area of , while the preliminary results of the first Ottoman census of 1885 (published in 1908) gave the population as 388,625. The accuracy of the population figures ranges from "approximate" to "merely conjectural" depending on the region from which they were gathered.
Bitlis and Muş were formerly included in the Eyalet of Erzurum. In 1875, they were detached and made a separate vilayet. The sanjak of Siirt was joined to the vilayet of Bitlis from Diyarbekir Vilayet in 1883–84.
Administrative divisions
Sanjaks of Bitlis Vilayet: Sanjak of Bitlis (Bitlis, Ahlat, Hizan, Mutki) Sanjak of Muş (Muş, Bulanık, Sason, Malazgirt, Varto) Sanjak of Siirt (Siirt, Eruh, Pervari, Şirvan, Kurtalan) Sanjak of Genç (Genç, Çapakçur, Kulp)