Il trionfo di Clelia ("The Triumph of Clelia") is an 18th-century Italian opera in three acts by the Czech composer Josef Mysliveček composed to a libretto by the Italian poet Metastasio. It was common in the 1760s for composers to set Metastasian texts written decades before. Exceptionally, the text for Il trionfo di Clelia, first produced in Vienna in 1762, was almost new when Mysliveček was commissioned to compose his setting for Turin, and all of the aria texts used for his setting derive from the original libretto. This opera (and all the rest of Mysliveček's operas) belong to the serious type in Italian language referred to as opera seria.