San Vittore is a municipality in the district of Moesa in the Swiss canton of Graubünden.
San Vittore is in the lower part of the valley of the Moesa river. It is just over 2 kilometres (1.2 miles) upstream of the border with the canton of Ticino. It is 6 kilometres (3.7 miles) upstream of Arbedo-Castione, where the Moesa river joins the Ticino river. At 278 metres (912 feet) above sea level, it is the lowest-lying community in Graubünden.