Achille et Polyxène (Achilles and Polyxena) is a tragédie lyrique containing a prologue and five acts based on Virgil's Aeneid with a French libretto by Jean Galbert de Campistron. The opera's overture and first act were composed by Jean-Baptiste Lully, who died from a conducting injury before he could complete the score. The prologue and the remaining acts are the work of his pupil Pascal Collasse who finished the work, eight months after Lully's death on March 22, 1687. The opera was first performed on November 7, 1687, by the Paris Opera at the Théâtre du Palais-Royal in Paris.

The libretto for this opera differs from those of Lully's earlier works with Philippe Quinault. Typically, Lully would begin his operas with a lively prologue, but this work has a somber prologue in which the Muses lament the king's desire for military expansion. Another difference is the tragic and somber ending of this opera in Act V. Lully usually ended his operas with a rousing ensemble number but this opera closes with the suicide of the heroine. The end of Act IV, the wedding scene, does contain a vibrant ensemble number at its close which would be more in keeping with a typical finale of one of Lully's operas.