The Elvo (Piedmontese: Elv) is a 53-kilometre (33 mi) torrent (an intermittent stream) in the Piedmont region of north-west Italy and is the principal tributary of the Cervo. It runs through the communes of Sordevolo , Occhieppo Superiore , Occhieppo Inferiore , Cerrione and Salussola in the Province of Biella , and of Carisio and Casanova Elvo in the Province of Vercelli .

The river’s valley is named after it as the Valle dell'Elvo. Here the municipalities are organized into two comunità montane: the Comunità Montana Alta Valle Elvo in the upper part of the valley, and the Comunità Montana Bassa Valle Elvo in the lower.

Many of the water courses of the Canavese and of the area of Biella—the torrent Orco, for example—are noted for the presence of gold-bearing sands. In the case of the Orco these are concentrated in the area of the Bessa nature reserve.