Saint Peter's Church (Peterskirche), the church of Theisberg (Deinsberg), functioned as early as the High Middle Ages as the hub of a great parish that reached east of the Glan from Nanzdiezweiler over to Mühlbach, within which there were branch churches in Bosenbach, Neunkirchen am Potzberg and Niedermohr.
Today, roughly 60% of Theisbergstegen's inhabitants are Evangelical and roughly 40% are Catholic.