Porto Santo Stefano (Italian: [ˈpɔrto ˈsanto ˈsteːfano]) is a seaport town on the west coast of Italy, in the municipality of Monte Argentario, in the Province of Grosseto, Tuscany.

The town is divided into four historical districts, each with its own coat of arms (gonfalone) banner:[3] Because of the increased exposure to pirate raids, the center had low priority during the rule of Aldobrandeschi and of the Republic of Siena, but with its entry into the State of Presidi in the mid-16th century, the town became a center of great importance in Argentario.

It was during this the construction of the Spanish Fort began, a powerful defensive structure that now hosts a permanent exhibition "Submerged Memories".

Besides the fortress, the territory still plays host to two Spanish lookout towers; Lividonia and dell'Argentiera, the latter situated on the slopes of Mount Argentario which dominates the whole Santo Stefano area.

[4][5] Notable events in the town include the Palio Marinaro, an annual 4,000-metre (2.5-mile) rowing regatta – a boat is called a "gozzo" (plural "gozzi") – which is held every August between the four districts.