Thomas Morley (1557 or 1558 – October 1602) was an English composer, theorist, editor and organist of the Renaissance, and the foremost member of the English Madrigal School. He was the most famous composer of secular music in Elizabethan England, and the only composer of the time, whose works have survived, to set verse by Shakespeare.

Morley was born in Norwich, in East Anglia; he was the son of a brewer. Most likely he was a singer in the local cathedral from his boyhood, and he became master of choristers there in 1583. However, Morley evidently spent some time away from East Anglia, for he later referred to the great Elizabethan composer of sacred music, William Byrd, as his teacher; while the dates he studied with Byrd are not known, they were most likely in the early 1570s. In 1588 he received his bachelor's degree from Oxford, and shortly thereafter was employed as organist at St. Paul's in London. His young son died the following year.

In 1588 Nicholas Yonge published his Musica transalpina, the collection of Italian madrigals fitted with English texts, which touched off the explosive and colorful vogue for madrigal composition in England. Morley evidently found his compositional direction at this time, and shortly afterwards began publishing his own collections of madrigals (11 in all).

Morley lived for a time in the same parish as Shakespeare, and a connection between the two has been long speculated, though never proven. His famous setting of "It was a lover and his lass" from As You Like It has never been established as having been used in a performance of Shakespeare's play, though the possibility that it was is obvious. Morley was highly placed by the mid-1590s and would have had easy access to the theatrical community; certainly there was then, as there is now, a close connection between prominent actors and musicians.

While Morley attempted to imitate the spirit of Byrd in some of his early sacred works, it was in the form of the madrigal that he made his principal contribution to music history. His work in the genre has remained in the repertory to the present day, and shows a wider variety of emotional color, form and technique than anything by other composers of the period. Predominantly his madrigals are light, quick-moving and easily singable; he took the aspects of Italian style that suited his personality and "Englished" them. Other composers of the English Madrigal School, for instance Thomas Weelkes and John Wilbye, were to write madrigals in a more serious or sombre vein.

In addition to his madrigals, Morley wrote instrumental music, including keyboard music (some of which is published in the Fitzwilliam Virginal Book), and music for the uniquely English consort of two viols, flute, lute, cittern and pandora.