The Câlnic Citadel (Romanian: Cetatea Câlnic; German: Burg Kelling) is a citadel located in Câlnic, Alba County, in the Transylvania region of Romania. It was built by a nobleman whose family later sold it to the local ethnic German Transylvanian Saxon community at a time when the area belonged to the Kingdom of Hungary. When still used for defensive purposes, the double walls encompassed a residential keep, storerooms and a Roman Catholic chapel that became Lutheran following the Reformation. Together with the surrounding village, the citadel forms part of the villages with fortified churches in Transylvania UNESCO World Heritage Site.