Rhäzüns (German pronunciation: [rɛˈtsyns]; Romansh: Razén, pronounced [ʁɐˈtsen]) is a municipality in the Imboden Region in the Swiss canton of Grisons .

Rhäzüns is first mentioned about 840 AD as Raezunne. It formed a single parish with Bonaduz until the Reformation. It was part of the Grey League from 1424. It was acquired by the House of Habsburg in 1497 but remained part of the Three Leagues for the purposes of jurisdiction. In the Treaty of Schönbrunn (1809), the Habsburg Monarchy ceded the lordship of Rhäzüns to France.