The Church of Norway is an evangelical Lutheran denomination of Protestant Christianity and by far the largest Christian church in Norway. The church became the state church of Norway around 1020, and was established as a separate church intimately integrated with the state as a result of the Lutheran reformation in Denmark–Norway which broke ties with the Holy See in 1536–1537; the King of Norway was the church's head from 1537 to 2012. Historically the church was one of the main instruments of royal power and official authority, and an important part of the state administration; local government was based on the church's parishes with significant official responsibility held by the parish priest.

During the Reformation, the territories ruled by the Danish-based House of Oldenburg converted from Catholicism to Lutheranism. After the break-up of the Kalmar Union in 1521/1523, these realms included the kingdoms of Denmark and Norway and the Duchies of Schleswig and Holstein, whereby Denmark also extended over today's Gotland and Øsel in Estonia.