Oreste ("Orestes", HWV A11, HG 48/102) is an opera by George Frideric Handel in three acts. The libretto was anonymously adapted from Giangualberto Barlocci’s L’Oreste (1723, Rome), which was in turn adapted from Euripides' Iphigeneia in Tauris.

The opera is a pasticcio (pastiche), meaning that the music of the arias was assembled from earlier works, mainly other operas and cantatas also by Handel. The recitatives and parts of the dances are the only parts composed specifically for this work. Handel had put together similar works before, fitting the music of pre-existent arias to new words, but this was the first time he had made an opera in this way using entirely his own music. He assembled a collection of his arias from the previous years, ranging from Agrippina of 1709 to Sosarme of 1732, binding the pre-existent music seamlessly together with the newly-written recitatives to create a new musical drama.

The opera is in Italian, although it was written and performed in England. The lead role was written for the castrato Giovanni Carestini. It is now performed by either a countertenor or soprano.