Quart (; Valdôtain: ; Issime ) is a comune (municipality) in the Italian region of Aosta Valley.
The Quart Castle, built starting from 1185 by Jacques de la Porte de Saint-Ours, founder of the Lords of Quart.
On the slopes below the castle, near Vollein, in 1968 remains of the Neolithic Vollein necropolis were found.
Other sights include a series of medieval watchtowers, such as the Chétoz Tower, the museum of Aosta Valley Railroads, and a fortified house in Povil.