Cazis (Romansh: Tgazas) is a municipality in the Viamala Region in the Swiss canton of Graubünden.

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).

[5] Before 2017, the municipality was located in the Thusis sub-district, of the Heinzenberg district, after 2017 it was part of the Viamala Region.

It consists of the linear village of Cazis and the hamlets of Ober- and Unterrealta, Luvreu, Ratitsch, Summaprada, Schauenberg and Valleina.

[9] The historical population is given in the following table:[4] Until 1800, the municipality spoke exclusively Sursilvan, a dialect of Romansh.

Today, the municipality is predominantly German-speaking population, with small Romansh- and Italian-speaking minorities.

[5] The Cresta (prehistoric settlement), Chapel St. Wendelin and the Catholic Church of St. Martin are listed as Swiss heritage sites of national significance.