Ardez is first mentioned circa 840 as Ardezis. Up to the 19th century, it was also known by the German name of Steinsberg. Lords de Ardetz are documented for the period 1161–1310. The lords of Tarasp, the bishop of Chur, Marienberg Abbey, the county of Tyrol and the bailiffs of Matsch had possessions and rights in Ardez. Steinsberg Castle, the castle of Ardez, was bought by the bishop of Chur before 1209. It was destroyed together with the village in 1499 during the Swabian War.
The old parish of Ardez also included Guarda, Lavin, Susch and Galtür in the Tyrolean Paznaun valley. In 1538 it became Protestant. The church was rebuilt 1576/1577. In 1622 Ardez was destroyed by Austrian troops; in 1652 it bought its freedom from Austria.
The inhabitants of Ardez farmed their arable land and raised cattle; until the middle of the 19th century they also exported wood to Tyrol. In 1913, Ardez railway station was opened. In 1975, the largely intact village of Ardez was chosen as one of four Swiss model villages for the European year of monument preservation; after that, numerous houses were renovated.