The Duchy of Sora was a semi-independent state in Italy, created in 1443 by King Alfonso I of Naples and dissolved in 1796. It occupied the south-eastern part of what is today Lazio, bordering what is now Abruzzo. Its capital was first Sora, and later, under the Boncompagni family, Isola di Sora.

Sora is a town and comune of Lazio, Italy, in the province of Frosinone. It is built in a plain on the banks of the Liri. This part of the valley is the seat of some important manufacturing, especially of paper mills. The area around Sora is famous for the costumes of its peasants.