Saas im Prättigau is a Swiss village in the Prättigau and a former municipality in the district of Prättigau/Davos in the canton of Graubünden. On 1 January 2016 the former municipality of Saas im Prättigau merged into the municipality of Klosters -Serneus.

Saas is first mentioned about 1290 as Säusch.

Saas has an area, as of 2006, of 26.8 km2 (10.3 sq mi). Of this area, 44% is used for agricultural purposes, while 26.2% is forested. Of the rest of the land, 2.1% is settled (buildings or roads) and the remainder (27.7%) is non-productive (rivers, glaciers or mountains).