Grabs is a municipality in the Wahlkreis (constituency) of Werdenberg in the Canton of St. Gallen in Switzerland .

Grabs is first mentioned in 841 as Quaravedes. In 979 it was mentioned as Quadravedes, then in 1235 as Grabdis and in 1253 as Graps.

Grabs has an area, as of 2006, of 54.7 km2 (21.1 sq mi). Of this area, 50% is used for agricultural purposes, while 32.2% is forested.