The Protestant Reformation was introduced to Künzelsau in 1556. The city is therefore predominantly Protestant. Since the move of 1824/25 move here from Ingelfingen it has been the seat of the deanery of the Evangelical Lutheran Church in Württemberg (see Church District Künzelsau). Evangelical congregations can be found in Belsenberg, Kocherstetten, Künzelsau and Morsbach, which include most Protestants from the other districts. Only the Protestants of the districts Berndshausen, Nitzenhausen and Wolf Sölden belong to the church community Buchenbach (community Mulfingen).