Sumvitg (Romansh pronunciation: [sumvitɕ]) is a municipality in the district of Surselva in the canton of Graubünden in Switzerland.
Sumvitg is first mentioned in 1175 as in Summovico.
Sumvitg has an area, as of 2006, of 101.8 km2 (39.3 sq mi). Of this area, 24.8% is used for agricultural purposes, while 26.8% is forested. Of the rest of the land, 1.3% is settled (buildings or roads) and the remainder (47.1%) is non-productive (rivers, glaciers or mountains).
The municipality is located in the Disentis sub-district of the Surselva district. It covers both sides of the Vorderrhein valley and the Val Sumvitg. It consists of the village of Sumvitg and the hamlets of Surrein, Rabius, Laus and Compadials as well as numerous farm houses. Until 1986 Sumvitg was known by its German name as Somvix.
Lag da Laus (Laus lake) is located above the hamlet of Laus.
Sumvitg has a population (as of 31 December 2014) of 1,240.As of 2008, 4.5% of the population was made up of foreign nationals. Over the last 10 years the population has decreased at a rate of -7.3%. Most of the population (as of 2000) speaks Romansh(88.0%), with German being second most common (10.0%) and Italian being third ( 1.1%).