Monte Argentario is a comune (municipality) and a peninsula belonging to the Province of Grosseto in the Italian region Tuscany, located about 150 km south of Florence and about 35 km south of Grosseto. The peninsula is connected with the mainland by three spits of land which form two lagoons, the Laguna di Ponente on the west side and the Laguna di Levante on the east side of the middle dam. The two main villages on Monte Argentario are Porto Santo Stefano, chief town, facing north, and Porto Ercole facing south.

The panoramic road Strada panoramica starts in Porto Santo Stefano allowing splendid views of the coast and the Tuscan Archipelago.

Monte Argentario borders the comune of Orbetello, which is located on the middle dam between the two lagoons.