The Walls of Dubrovnik are a series of defensive stone walls surrounding the city of Dubrovnik in southern Croatia. With numerous additions and modifications throughout their history, they have been considered to be amongst the great fortification systems of the Middle Ages, as they were never breached by a hostile army during this time period. In 1979, the old city of Dubrovnik, which includes a substantial portion of the old walls of Dubrovnik, joined the UNESCO list of World Heritage Sites.
The oldest systems of fortifications around the town were likely wooden palisades. Today's intact city walls, constructed mainly during the 12th–17th centuries, mostly a double line, have long been a source of pride for Dubrovnik. The walls run an uninterrupted course of approximately 1,940 metres in length, encircling most of the old city, and reach a maximum height of about 25 metres. The bulk of the existing walls and fortifications were constructed during the 14th and 15th centuries, but were continually extended and strengthened up until the 17th century.