The Bulgarian Orthodox Church, legally the Patriarchate of Bulgaria, is an autocephalous Eastern Orthodox jurisdiction based in Bulgaria. It is the first medieval recognised patriarchate outside the Pentarchy and the oldest Slavic Orthodox church, with some 6 million members in Bulgaria and between 1.5 and 2 million members in a number of other European countries, Asia, the Americas, Australia, and New Zealand. It was recognized as autocephalous in 1945 by the Ecumenical Patriarchate of Constantinople.

Bulgaria, officially the Republic of Bulgaria, is a country in Southeast Europe. Located west of the Black Sea and south of the Danube river, Bulgaria is bordered by Greece and Turkey to the south, Serbia and North Macedonia to the west, and Romania to the north. It covers a territory of 110,994 square kilometres (42,855 sq mi) and is the 16th largest country in Europe. Sofia is the nation's capital and largest city; other major cities include Burgas, Plovdiv, and Varna.