The local parish church, dedicated to Saint Leonard, belongs to the Roman Catholic Diocese of Novo Mesto. It was first mentioned in written documents dating to 1360. The original structure was damaged in the 1511 Idrija earthquake and a new church was built in 1520. It was surrounded by a double fortified wall with defensive towers to protect against Ottoman attacks, with granaries above and cellars below, and a single entrance accessed by a drawbridge over a moat. The internal wall was razed in 1844 and the rubble was used to build a schoolhouse. The external wall was lowered to the level of the cemetery wall in 1856 and then removed entirely when the cemetery was abandoned. The current church has a Baroque character built on a Gothic structure. Two chapels were added to the nave in 1720 and the interior of the church was reworked and refurnished in the Baroque style. The bell tower was increased in height, and towards the end of the 19th century it was outfitted with a neo-Gothic metal roof. The main altar is a high-Baroque wooden work; an inscription indicated that it was created in 1764 by Franz Fajenz and Anton Kastelec, and renovated in 1865 by Leopold Goetzl. The side altars in the nave are in the Rococo style. The stone baptismal basin bears the year 1642, and one bell dates from 1769. Mozelj was elevated to a parish in 1509.