| Cosio Valtellino | |
| Official Name: | Comune di Cosio Valtellino |
| Coordinates: | 46.1333°N 41°W |
| Region: | Lombardy |
| Province: | Sondrio (SO) |
| Frazioni: | Cosio Stazione, Mellarolo, Piagno, Regoledo, Sacco |
| Mayor: | Alan Vaninetti |
| Area Total Km2: | 23.9 |
| Population Total: | 5413 |
| Population As Of: | 31 August 2010[1] |
| Population Demonym: | Cosiesi |
| Elevation M: | 231 |
| Postal Code: | 23013 |
| Area Code: | 0342 |
Cosio Valtellino is a comune (municipality) in the Province of Sondrio in the Italian region Lombardy, located about 80km (50miles) northeast of Milan and about 25km (16miles) west of Sondrio.
Cosio Valtellino borders the following municipalities: Bema, Cercino, Mantello, Morbegno, Rasura, Rogolo, Traona.
The principal seat of Galbusera (confectionery company) resides in Cosio.