Johan Ernst Gunnerus was a Norwegian bishop and botanist. Gunnerus was born at Christiania. He was bishop of the Diocese of Nidaros from 1758 until his death and also a professor of theology at the University of Copenhagen.

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.