Arosa is a town and a municipality in the Plessur Region in the canton of the Grisons in Switzerland. It is both a summer and a winter tourist resort.

On 1 January 2013, the former municipalities of Calfreisen , Castiel, Langwies , Lüen , Molinis , Peist and St. Peter-Pagig merged into the municipality of Arosa.

At the end of 2013 the Arosa ski resort was linked with Lenzerheide by cable-car, creating the new ski resort of Arosa Lenzerheide; since that change, transport passes have been valid in both resorts.

The official language of Arosa is (the Swiss variety of Standard) German, but the main spoken language is the local variant of the Alemannic Swiss German dialect.