Arbatax (Italian pronunciation: [arbataks]) is the greatest hamlet (frazione) of Tortolì, Sardinia, in Italy. With almost 5,000 inhabitants, it is also the third town in its province (Ogliastra) by population, after Lanusei municipality (5,700) and Tortolì (5,300). The name is derived from the Arabic for "14th Tower" and refers to the nearby Saracen watchtower. The town is situated by Tyrrhenian Sea, 5 km west of Tortolì.

The port is used by ferries from Civitavecchia and is also monopolized by the marine construction company Intermare, who build gas rigs and vessels. The marina is one of the cheapest in Sardinia and provides an excellent base for exploring the splendid Eastern coastline.

The famous "Trenino verde" tourist train chugs up into the mountainous hinterland.