Montagna in Valtellina is a comune (municipality) in the Province of Sondrio in the Italian region Lombardy, located about 100 kilometres (62 mi) northeast of Milan and about 3 kilometres (2 mi) northeast of Sondrio.

Montagna in Valtellina borders the following municipalities: Caspoggio, Chiuro, Faedo Valtellino, Lanzada, Piateda, Poggiridenti, Ponte in Valtellina, Sondrio, Spriana, Torre di Santa Maria, Tresivio.