Cazis (Romansh: Tgazas) is a municipality in the Viamala Region in the Swiss canton of the Grisons . On 1 January 2010 the municipalities of Portein , Präz , Sarn and Tartar merged into the municipality of Cazis.

Cazis is first mentioned in 926 as Cacias.

Cazis has an area, as of 2006, of 7.3 km2 (2.8 sq mi). Of this area, 41% is used for agricultural purposes, while 41.1% is forested. Of the rest of the land, 13.6% is settled (buildings or roads) and the remainder (4.3%) is non-productive (rivers, glaciers or mountains).