English poet best known for his religious and scientific poem The Purple Island.

He was the elder son of Giles Fletcher the Elder and brother of Giles Fletcher the Younger. He was educated at Eton and at King's College, Cambridge. Fletcher became chaplain to Sir Henry Willoughby, who presented him in 1621 to the rectory of Hilgay, Norfolk, where he spent the rest of his life.

His greatest work, The Purple Island, was published in 1633. It included the Piscatorie Eclogs and other Poetical Miscellanies. The Purple Island: or the Isle of Man, is a poem in 12 cantos describing allegorically the human physiology and soul. The manner of Edmund Spenser is employed throughout, and the chief charm of the poem is considered by critics to be its descriptions of rural scenery. The Piscatorie Eclogs are pastorals, the characters of which are represented as fisherboys on the banks of the Cam, and are interesting for the light they cast on the biography of the poet himself (Thyrsil) and his father (Thelgon), and on Phineas' friendship with Cambridge men. Fletcher's poetry has not the sublimity sometimes reached by his brother Giles.