Giovanni Battista Draghi, best known as Pergolesi or Giovanni Battista Pergolesi, was an Italian composer, violinist and organist.

Born in Jesi in what is now the Province of Ancona (but was then the Papal States), he was commonly given the nickname "Pergolesi", a demonym indicating in Italian the residents of Pergola, Marche, the birthplace of his ancestors. He studied music in Jesi under a local musician, Francesco Santini, before going to Naples in 1725, where he studied under Gaetano Greco and Francesco Feo among others. He spent most of his brief life working for aristocratic patrons like the Colonna principe di Stigliano, and duca Marzio IV Maddaloni Carafa.

Pergolesi was one of the most important early composers of opera buffa. His opera seria, Il prigionier superbo, contained the two-act buffa intermezzo, La serva padrona (1733), which became a very popular work in its own right. When it was performed in Paris in 1752, it prompted the so-called Querelle des Bouffons ("quarrel of the comic actors") between supporters of serious French opera by the likes of Jean-Baptiste Lully and Jean-Philippe Rameau and supporters of new Italian comic opera. Pergolesi was held up as a model of the Italian style during this quarrel, which divided Paris's musical community for two years.

Among Pergolesi's other operatic works are his first opera La conversione e morte di San Guglielmo (1731), Lo frate 'nnamorato (1732, to a text in the Neapolitan language), L'Olimpiade (1735) and Il Flaminio (1735). All his operas were premiered in Naples, apart from L'Olimpiade, which was first given in Rome.

Pergolesi also wrote sacred music, including a Mass in F and two Salve Regina settings. It is his Stabat Mater (1736), however, for soprano, alto, string orchestra and basso continuo, which is his best-known sacred work. It was commissioned by the Confraternità dei Cavalieri di San Luigi di Palazzo, which presented an annual Good Friday meditation in honor of the Virgin Mary. Pergolesi's work replaced one composed by Alessandro Scarlatti only nine years before, but which was already perceived as "old-fashioned," so rapidly had public tastes changed.

While classical in scope, the opening section of the setting demonstrates Pergolesi's mastery of the Italian baroque durezze e ligature style, characterized by numerous suspensions over a faster, conjunct bassline. The work remained popular, becoming the most frequently printed musical work of the 18th century, and being arranged by a number of other composers, including Johann Sebastian Bach, who used it as the basis for his cantata Tilge, Höchster, meine Sünden (Root out my sins, Highest One), BWV 1083.

Pergolesi wrote a number of secular instrumental works, including a violin sonata and a violin concerto. A considerable number of instrumental and sacred works once attributed to Pergolesi have since been shown to be misattributed. Much of Igor Stravinsky's ballet Pulcinella, which ostensibly reworks pieces by Pergolesi, is actually based on works by other composers, especially Domenico Gallo. The Concerti Armonici are now known to have been composed by Unico Wilhelm van Wassenaer. Many colorful anecdotes related by Pergolesi's 19th-century biographer, Francesco Florimo, were later revealed as hoaxes, though they had furnished material for two 19th-century operas broadly based on Pergolesi's career.

Giovanni Battista Pergolesi died at the age of 26 in Pozzuoli from tuberculosis and was buried at the Franciscan monastery one day later.