Le Villi (The Willis or The Fairies) is an opera–ballet in two acts (originally one) composed by Giacomo Puccini to an Italian libretto by Ferdinando Fontana, based on the short story "Les Willis" by Jean-Baptiste Alphonse Karr. Karr's story was in turn based in the Central European legend of the Vila, also used in the ballet Giselle. The opera, in its original one-act version, was first performed at the Teatro Dal Verme, Milan, on 31 May 1884.

Le Villi is Puccini's first stage work. It was written for an 1883 competition of one-act operas by the publisher Sonzogno in his periodical Il teatro illustrato, but did not even earn an honourable mention. According to Mosco Carner, this may have been because it was written in such haste that the score was all but illegible. His supporters, who included Arrigo Boito, funded the first production, whose favorable reception led to publication by Giulio Ricordi. Puccini's mother received the following telegram on the night of premiere at the Teatro dal Verme on 31 May 1884: "Theatre packed, immense success; anticipations exceeded; eighteen calls; finale of first act encored thrice"'. Ricordi urged the composer to expand the work, and Puccini did, producing a new version later that year, which was followed by modifications in 1885, and the final version in 1889. A performance typically lasts 64 minutes.