Valtellina (From The It. Vol Tellina; Ger. Veltellin Or Veltlin), a valley of Lombardy, in the province of Sondrio, separated by the Rhaetian Alps from the Engadine, bounded N. by the Swiss canton of Grisons, N. E. by Tyrol, from which it is separated by the Ortler and the Stilfser Joch, S. by the provinces of Brescia, Bergamo, and Como, and W. by the lake of Como and the valley of Chiavenna. The valley of Valtellina proper is 45 m. long, and with its continuation, the Valley of Bormio, 55 m. Together with the valley of Chiavenna it constitutes the province of Sondrio; and the three valleys are sometimes collectively called Valtellina. It is remarkable for fertility, the chief products being wine, grain, fruit, and cheese. The three valleys belonged in the latter part of the middle ages to the dukes of Milan. They became part of Grisons in 1512, and through the influence of France remained in possession of the Swiss despite the efforts of Austria during the thirty years' war to secure the territory. In 1797 Valtellina became part of the Cisalpine republic, and in 1804 of the French department of Adda. In 1814 it came under Austrian rule as part of Sondrio, and in 1859 under Italian rule.

Besides Sondrio, the capital of the province, the most noted localities are Teglio, formerly the capital of Valtellina; Grossotto, where a fearful massacre of Protestants took place on July 19,1620, known as the Valtellina massacre; and Morbegno, where the inquisition took up its headquarters after this episode, and which derived its name from the prevailing malaria.