Rumelia (or Roumelia) (in Turkish Rumili, the East Roman or Byzantine Empire), a name commonly used, from the 15th century onwards, to denote the part of the Balkan Peninsula subject to Turkey.

More precisely it was the country bounded North by Bulgaria, West by Albania and South by the Morea, or in other words the ancient provinces, including Constantinople and Thessaloniki, of Thrace and Macedonia. The name was ultimately applied more especially to a province composed of central Albania and western Macedonia, having Monastir for its chief town. Owing to administrative changes effected between 1870 and 1875, the name ceased to correspond with any political division. Eastern Rumelia was constituted an autonomous province of the Turkish empire by the Berlin treaty of 1878, but on the September 18, 1885, after a bloodless revolution, it was united with Bulgaria.