Rumelia (or Roumelia) (in Turkish Rumeli, 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 the Ottoman Empire. However the word "Rumeli" literally translates as "the land of Romans" in reference to Eastern Roman Empire, and hence during 11th and 12th century it was widely used for Anatolia as it had been recently conquered from the Eastern Romans.

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 Ottoman Empire by the Treaty of Berlin, 1878, but on the September 18, 1885, after a bloodless revolution, it was united with Bulgaria.

Today the word "Rumeli" is sometimes used to indicate the part of Turkey which is in Europe.