L'incoronazione di Poppea (SV 308, The Coronation of Poppaea) is an Italian opera by Claudio Monteverdi, with a libretto by Giovanni Francesco Busenello, first performed at the Teatro Santi Giovanni e Paolo in Venice during the 1643 carnival season. One of the first operas to use historical events and people, it describes how Poppaea, mistress of the Roman emperor Nero, is able to achieve her ambition and be crowned empress. The opera was revived in Naples in 1651, but was then neglected until the rediscovery of the score in 1888, after which it became the subject of scholarly attention in the late 19th and early 20th centuries. Since the 1960s, the opera has been performed and recorded many times.

The original manuscript of the score does not exist; two surviving copies from the 1650s show significant divergences from each other, and each differs to some extent from the libretto. How much of the music is actually Monteverdi's, and how much the product of others, is a matter of dispute. None of the existing versions of the libretto, printed or manuscript, can be definitively tied to the first performance at the Teatro Santi Giovanni e Paolo, the precise date of which is unknown. Details of the original cast are few and largely speculative, and there is no record of the opera's initial public reception. Despite these uncertainties, the work is generally accepted as part of the Monteverdi operatic canon, his last and perhaps his greatest work.

In a departure from traditional literary morality, it is the adulterous liaison of Poppea and Nerone which triumphs, although this victory is demonstrated by history to have been transitory and hollow. Moreover, in Busenello's version of the story all the major characters are morally compromised. Written when the genre of opera was only a few decades old, the music for L'incoronazione di Poppea has been praised for its originality, its melody, and for its reflection of the human attributes of its characters. The work helped to redefine the boundaries of theatrical music, and established Monteverdi as the leading musical dramatist of his time.