Don Sanche, ou Le château de l'amour (English: Don Sanche, or The Castle of Love), S.1, is an opera in one act composed in 1824-25 by Franz Liszt, with French libretto by Théaulon and de Rancé, based on a story by Jean-Pierre Claris de Florian. For 30 years it was believed to be lost until it was rediscovered in 1903. The first modern performance took place in 1977, 74 years after its rediscovery.

The opera appears to have been ready as early as September 1824. It is known that on 20 June 1825, Liszt presented an overture in his second Birmingham concert. This is probably the one from Don Sanche since no other overture exists from this period. The manuscript contains many passages that are reminiscent of the style of his compositions teacher Ferdinando Paer, who admittedly helped Liszt with orchestration. Liszt received a mere 170 francs for his opera. Later in the 1840s, Liszt tried to pursue a career as an opera composer. He planned, sketched, but never completed several other operas. Among them a work in the Italianate style known as Sardanapale, of which 111 sketched pages exists.