The Bosnian Church was a schismatic Christian church in medieval Bosnia and Herzegovina that was independent from and considered heretical by both the Catholic and the Eastern Orthodox churches.

The history of Bosnia and Herzegovina in the Middle Ages refers to the time period between the Roman era and the 15th-century Ottoman conquest. The Early Middle Ages in the Western Balkans saw the region reconquered from barbarians (Ostrogoths) by the Byzantine Emperor Justinian I, followed by raids and migrations carried out by Slavic peoples in the 6th and 7th centuries. The first mention of a distinct Bosnian region comes from the 10th-century Byzantine text De Administrando Imperio. By the late 9th and early 10th century, Latin priests had Christianized much of Bosnia, with some areas remaining unconverted. In the High Middle Ages, Bosnia experienced economic stability and peace under the Ban Kulin who ruled over Banate of Bosnia from 1180 to 1204 and strengthened its ties with the Republic of Ragusa and with Venice. The Kingdom of Bosnia emerged in the Late Middle Ages (1377). The kingdom faced internal and external conflicts, eventually falling under Ottoman rule in the late 15th and early 16th centuries.