Prato-Sornico is a former municipality in the district of Vallemaggia in the canton of Ticino, Switzerland .

The municipality contained the villages Prato and Sornico. These entities were former municipalities of their own, having been merged to form Prato-Sornico in 1864.

In 2004 Prato-Sornico municipality was merged with the other, neighboring municipalities Broglio, Brontallo , Fusio , Menzonio and Peccia to form a new and larger municipality Lavizzara .

Prato and Sornico were first mentioned in 1374.

Prato and Sornico, along with Broglio, Fusio and Peccia, formed the valley community of Lavizzara.