The Klostertal, lit. 'Cloister Valley', is an alpine valley in Vorarlberg , in Austria. It branches off at Bludenz and extends about 30 km (19 mi) to the east to the Arlberg and the border with Tyrol. It consists of the three communities of Klösterle am Arlberg, Dalaas and Innerbraz and the three Bludenz towns Bings, Radin and Außerbraz with an area of 193.6 km2 (74.7 sq mi) and about 4,700 inhabitants (as of 2017).

The valley opens to the east of the district capital Bludenz and is characterized by the south and north steeply towering mountain ranges of the Lechquellen Mountains and the Verwalls mountain range. The Alfenz flows through the Klostertal from Stuben am Arlberg (district of Klösterle/Arlberg) to the Ill at Bludenz. The bottom of the valley is rising steadily, which is reflected by the fact that the sea level of the settlement areas ranges between 600 m (2,000 ft) in the west and 1,400 m (4,600 ft) in the east.