The Walls of Ston (Croatian: Stonske zidine) are a series of defensive stone walls, originally more than 7 kilometres (4.3 mi) long, that surrounded and protected the city of Ston, in Dalmatia, part of the Republic of Ragusa, in what is now southern Croatia. Their construction was begun in 1358. On the Field Gate of the Walls (Poljska vrata) there is a Latin inscription which dates from 1506. Today, it is one of the longest preserved fortification systems in the world.

The Walls of Ston were known as the "European Great Wall of China".