Dornbirn (German pronunciation: [ˈdɔʁnbɪʁn] ) is a city in the westernmost Austrian state of Vorarlberg. It is the administrative centre for the district of Dornbirn, which also includes the town of Hohenems, and the market town Lustenau.

Dornbirn is the largest city in Vorarlberg and the tenth largest city in Austria. It is an important commercial and shopping centre.

Dornbirn is located at 437 metres above sea level in the Alpine Rhine Valley, at the foot of the Karren mountain, part of the Bregenz Forest Mountain chain at the edge of the Eastern Alps. It is near the borders to Switzerland, Germany and Liechtenstein.