The canton of St. Gallen or St Gall (German: Kanton St. Gallen [zaŋkt ˈɡalən] ; Romansh: Chantun Son Gagl; French: Canton de Saint-Gall; Italian: Canton San Gallo) is a canton of Switzerland. Its capital is St. Gallen.

Located in northeastern Switzerland, the canton has an area of 2,026 km2 (782 sq mi) (5% of Switzerland) and a resident population close to half a million as of 2015 (6% of Switzerland).