Les Danaïdes is an opera by Antonio Salieri, in five acts: more specifically, it is a tragédie lyrique. The opera was set to a libretto by François-Louis Gand Le Bland Du Roullet and Louis-Théodore de Tschudi, who in turn adapted the work of Ranieri de' Calzabigi (without permission). Calzabigi originally wrote the libretto of Les Danaïdes for Christoph Willibald Gluck, but the aged composer, who had just experienced a stroke, was unable to meet the Opéra's schedule and so asked Salieri to take it over. The plot of the opera is based on Greek tragedy and revolves around the deeds of the mythological characters Danaus and Hypermnestra.

Emperor Joseph II assured that Salieri wrote the music "almost under the dictée of Gluck," in a letter (dated 31 March 1783) to Count Mercy-Argenteau, the Austrian ambassador in Paris. Then Mercy told the directors of the Opéra that Gluck had composed the first two acts, and Salieri supplied the third act's music (Mercy did not realize the opera was in five acts). Even when the libretto was published, Gluck and Salieri shared billing as the composers.

Though flattered, Gluck was not foolish enough to risk too close an association with young Salieri's work and diplomatically informed the press: "The music of Danaïdes is completely by Salieri, my only part in it having been to make suggestions which he willingly accepted." Gluck, who had been devastated by the failure of his last Paris opera, Echo et Narcisse, was concerned that Les Danaïdes would suffer a similar fate. He wrote to Roullet the same day that the opera premiered, crediting Salieri with the entire work, and the press noted this confession. Salieri made a positive twist on Gluck’s statement, claiming that he was "led by [Gluck’s] wisdom and enlightened by his genius".

Les Danaïdes was orchestrated for 2 traversos, 2 oboes, 2 clarinets, 2 bassoons, 2 horns, 2 trumpets, 3 trombones, first violins, second violins, violas, cellos, double-basses, timpani and harpsichord.

Salieri's use of trombones to delineate infernal moments in the drama has often been viewed of as a precedent for Mozart's similar orchestration in Don Giovanni. Stylistically, Salieri combined the direct simplicity of Gluck's innovations with the concern for melody of Italian composers, though the frequent use of chorus owes much to French traditions, as did the munificent staging, which much impressed Berlioz.

Hypermnestra's soprano, which dominates the opera in a manner that anticipates the soprano-centered opera of Luigi Cherubini and Gaspare Spontini, is technically well written, and although Salieri didn't develop the basic material beyond the formulas inherited from Gluck, his music is more melodic and lyrical. The fine soprano role, the tremendously grim finale, and the brevity of Les Danaïdes (ten minutes under two hours) have ensured that the opera has made it onto CD.

Salieri was certainly aware of his role in continuing the Gluckian tradition of the tragédie lyrique, with the attention to the relationship between text and music. The orchestral recitatives, choruses, and ballets also follow the model for French opera supplied by Gluck. Furthermore, the music itself is infused with the 'noble simplicity' that characterizes the older composer's reform operas.

At the same time, Les Danaïdes marked a progression from number opera to the dramatically more consequent through-composed scenic opera. A lyricism associated with Niccolò Piccinni and Antonio Sacchini, who also composed for Paris, can also be heard in Les Danaïdes.