Hohenems (High Alemannic: Ems) is a town in the Austrian state of Vorarlberg in the Dornbirn district. It lies in the middle of the Austrian part of the Rhine valley. With a population of 16,946, it is the fifth largest municipality in Vorarlberg and currently has the fastest population growth in the state. Hohenems' attractions include a Renaissance palace dating back to the 16th century, a Jewish history museum, and the old town center.

The town is located at 432 metres (1,417 feet) above sea level, about 16 km (10 miles) south of Lake Constance. Hohenems extends for 5.5 km (3.4 mi) from north to south and 8.2 km (5.1 mi) from west to east. Its total area is 29 square kilometres (11 sq mi), of which 42% is covered with forest. The oxbow lake of the river Rhine in the west, forming the border of Austria as well as EU to Switzerland, and the mountainside in the east is at the narrowest point of the Austrian Rhine valley. The Schlossberg ("castle mountain"), elevation 740 metres (2,428 feet), offers a distinctive backdrop to the town center.

Hohenems is divided into the neighborhoods of Markt (centre), Oberklien and Unterklien (north), Hohenems-Reute (east), Schwefel (south) and Herrenried (west). It is surrounded by six other communities, Lustenau and Dornbirn in the Dornbirn district (north and east), Fraxern, Götzis and Altach in the Feldkirch district (south) and Diepoldsau in the Swiss canton St. Gallen (west).

The summit of the Schlossberg rock, within 45 minutes walk from the town center, is crowned by the ruins of Alt-Ems, a castle dating back to the 9th century CE. From the 12th century it was among the largest fortifications in the south of the German kingdom. The stronghold was very extensive, with a length of up to 800 m (2,625 ft) and a width of 85 m (280 ft). It reached its peak of fame from the 13th to 16th centuries, as a residence of many lords and knights of Hohenems. As they were loyal ministeriales of the Hohenstaufen dynasty, the castle served as a prison for notable prisoners like the Norman king William III of Sicily, who probably died there in 1198.

Hohenems was granted municipal rights and liberties (German Stadtrecht) in 1333, but the town did not make use of these rights for 650 years until, in 1983, the government of Vorarlberg granted Hohenems full status as a "municipality".

The Burg Neu-Ems (also called "Schloss Glopper"), built in 1343, is located on a mountain promontory near Alt-Ems. In 1407 both castles were destroyed during the Appenzell Wars, but rebuilt shortly afterwards. Burg Neu-Ems is still intact today and is the private property of the Waldburg-Zeil family.

The Renaissance palace stands at the foot of the Schlossberg and dominates the main square of town, the Schlossplatz. It was built from 1562 to 1567, according to plans by architect Martino Longhi the Elder at the initiative of Cardinal Marcus Sittich Hohenems (Altemps), architect who also designed the Cardinal’s palace in Rome. Religious wars and a plague decimated the population and devastated the area over the next century, ironically the time of the greatest power of the (Protestant) Counts of Hohenems, when they acquired Vaduz Castle from what was later to become Liechtenstein. Two manuscripts of the Nibelungenlied were found in Hohenems, in 1755 and 1779, in the palace's library.

The first café (1797), bank and printing office (1920) of Vorarlberg were opened in Hohenems.