Burg am Leopoldsberg is a medieval castle located at the summit of the Leopoldsberg, part of the Wienerwald in the Döbling district of Vienna, Austria. Originally known as Burg Ka(h)lenberg, it served as a princely castle for the Babenberg and later the Habsburg families. The castle complex includes the Church of St. Leopold, which has been open to the public since June 2018. Since 1787, the site has been owned by the Stift Klosterneuburg and is currently leased.