The Diocese of Agder og Telemark is a diocese of the Church of Norway, covering all of Agder county and most of Vestfold og Telemark county in Norway. The cathedral city is Kristiansand, Norway's fifth largest city. Kristiansand Cathedral serves as the seat of the presiding Bishop. The bishop since 2013 has been Stein Reinertsen. As of 1 January 2003, there were 347,324 members of the Church of Norway in the diocese.

Stein Reinertsen is a Norwegian Lutheran clergyman who since January 2013 has been bishop in the Diocese of Agder og Telemark of the Church of Norway.