Sumvitg (Romansh pronunciation: [ˈsumvitɕ] ; German: Somvix) is a municipality in the Surselva Region in the canton of the Grisons 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).

Before 2017, the municipality was located in the Disentis sub-district of the Surselva district, after 2017 it was part of the Surselva Region.