Don Carlos is an 1867 five-act grand opera composed by Giuseppe Verdi. It was set to a French-language libretto written by Joseph Méry and Camille du Locle, which drew inspiration from Friedrich Schiller's 1787 play Don Karlos, Infant von Spanien, as well as various incidents from Eugène Cormon's 1846 play Philippe II, Roi d'Espagne.
While the original libretto was in French, the opera is most frequently performed in Italian translation under the title Don Carlo. The work remains a significant piece of Verdi's operatic output based on historical and dramatic source material from the late 18th and early 19th centuries.