St Ralph Sherwin (1550–1 December 1581) was an English Roman Catholic martyr and saint. He was born at Rodsley , Derbyshire, and was educated at Eton College. In 1568, he was nominated by Sir William Petre to one of the eight fellowships which he had founded at Exeter College, Oxford, probably influenced by Sherwin's uncle, John Woodward, who from 1556 to 1566 had been rector of Ingatestone, Essex, where Petre lived. A talented classical scholar, Sherwin graduated Master of Arts on 2 July 1574, and the following year converted to Roman Catholicism and fled abroad to the English College at Douai, where he was ordained a priest by the Bishop of Cambrai on 23 March 1577. On 2 August 1577, he left for Rome, where he stayed at the English College for nearly three years, becoming a Jesuit.

On 18 April 1580, Sherwin and thirteen companions left Rome for England. On 9 November 1580, he was arrested while preaching in the house of Nicholas Roscarrock in London and imprisoned in the Marshalsea, where he converted many fellow prisoners, and on 4 December was transferred to the Tower of London, where he was tortured on the rack and then laid out in the snow. He is said to have been personally offered a bishopric by Elizabeth I if he apostasised, but refused. After spending a year in prison he was finally brought to trial with Edmund Campion on a trumped up charge of treasonable conspiracy. He was convicted in Westminster Hall on 20 November 1581. Eleven days later he was drawn to Tyburn on a hurdle along with Alexander Briant , where he was hanged, drawn and quartered. His last words were "Jesu, Jesu, Jesu, esto mihi Jesus!"

Sherwin was the first member of the English College in Rome to be martyred. He was beatified in the late 19th century and canonised in 1970 as one of the Forty Martyrs of England and Wales. His feast day is on 1 December, the day of his martyrdom.