Girolamo Frescobaldi (September, 1583 – March 1, 1643) was one of the most important composers of keyboard music in the late Renaissance and early Baroque periods.

Frescobaldi was born in Ferrara. He studied under the organist and famous madrigalist Luzzasco Luzzaschi at Ferrara and is also considered to have been influenced by Carlo Gesualdo, who was in Ferrara at the time. His patron Enzo Bentivoglio helped him get the position as an organist at the church of Santa Maria in Trastevere in Rome in the spring of 1607. Together with him he travelled to the Low Countries before he became organist of St Peter's in Rome in 1608, a post he held until his death. From 1628 to 1634 he was organist at the court of the Medicis in Florence.

He wrote a large number of works for the organ and harpsichord, including toccatas, capricci , fantasie, canzonas, ricercare (a generic name for any contrapuntal piece), dances and variations. Among his best known works is the Fiori musicali (1635), a collection of organ works designed to be played during the mass service. He published two books of toccatas between 1615 and 1637, which contain the Cento Partite, one of his most virtuosic and experimental works. His vocal music, which includes a number of masses, motets and madrigals, and his instrumental music, is less well known, in spite of the "1st Volume of Canzoni to be played with any type of instrument" published in 1628.

Frescobaldi was one of the inventors of the modern conception of tempo, making a compromise between the ancient white mensural notation with a rigid tactus and the modern notion of tempo, which is characterized by acceleration and deceleration within a piece.

Frescobaldi's music was a very important influence on later composers, among them Johann Jakob Froberger and Johann Sebastian Bach (Bach is known to have owned a copy of Frescobaldi's Fiori musicali).