Nidaros is a diocese in the Lutheran Church of Norway. It covers Trøndelag county in Central Norway and its cathedral city is Trondheim, which houses the well-known Nidaros Cathedral. Since 10 September 2017, the Bishop of Nidaros is Herborg Finnset. The Bishop Preses, currently Olav Fykse Tveit is also based at the Nidaros Cathedral. The diocese is divided into nine deaneries (prosti). While the Bishop Preses holds episcopal responsibility within the Nidaros domprosti (deanery) in Trondheim, the Bishop of Nidaros holds episcopal authority of the other eight deaneries as well as the language based parish of the Southern Sámi.

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.