La clemenza di Tito, K. 621, is an opera seria in two acts composed by Wolfgang Amadeus Mozart to an Italian libretto by Caterino Mazzolà, after Pietro Metastasio. Mozart began the work while he was finishing Die Zauberflöte, the last of his principal operas. La clemenza di Tito premiered on 6 September 1791 at the Estates Theatre in Prague.

Anton Paul Stadler was an Austrian clarinet and basset horn player for whom Wolfgang Amadeus Mozart wrote, amongst others, both his Clarinet Quintet and Clarinet Concerto. Stadler's name is inextricably linked to Mozart's compositions for these two instruments.