Sir John Cheke (16 June 1514 – 13 September 1557) was an English classical scholar and statesman, notable as the first Regius Professor of Greek at Cambridge University.

The son of Peter Cheke, esquire - bedell of Cambridge University, he was educated at St John's College, Cambridge, where he became a fellow in 1529. While there he adopted the principles of the Reformation. His learning gained him an exhibition from the king, and in 1540, on Henry VIII's foundation of the regius professorships, he was elected to the chair of Greek. Amongst his pupils at St John's were William Cecil, later Lord Burghley, who married Cheke's sister Mary, and Roger Ascham, who in The Scholemaster gives Cheke the highest praise for scholarship and character. Together with Sir Thomas Smith, he introduced a new method of Greek pronunciation very similar to that commonly used in England in the 19th century. It was strenuously opposed in the University, where the continental method prevailed, and Bishop Gardiner, as chancellor, issued a decree against it (June 1542); but Cheke ultimately triumphed.

On 10 July 1544 he was confirmed as tutor to the future King Edward VI of England, to teach him "of toungues, of the scripture, of philosophie and all liberal sciences". After his pupil's accession to the throne he continued in this role.

About 1547 Cheke married Mary, daughter of Richard Hill, sergeant of the wine cellar to Henry VIII, and by her he had three sons. The descendants of one of these, Henry, known only for his translation of an Italian morality play Freewyl (Tragedio del Libero Arbitrio) by Nigri de Bassano, settled at Pyrgo in Essex.

Cheke was active in public life; he sat, as member for Bletchingley, for the parliaments of 1547 and 1552 - 1553; he was made provost of King's College, Cambridge (1 April 1548), was one of the commissioners for visiting that university as well as the University of Oxford and Eton College, and was appointed with seven divines to draw up a body of laws for the governance of the church. On 11 October 1551 he was knighted; in June 1553 he was made one of the secretaries of state, and joined the privy council.

His Protestantism led him to follow the Duke of Northumberland, and he filled the office of secretary of state for Lady Jane Grey during her nine days' reign. In consequence, Queen Mary threw him into the Tower of London (27 July 1553), and confiscated his property. He was, however, released on 3 September 1554, and granted permission to travel abroad. He went first to Basel, then visited Italy, giving lectures in Greek at Padua, where he entertained Sir Philip Hoby. He finally settled at Strasbourg, teaching Greek for his living.

In the spring of 1556 he visited Brussels to see his wife; on his way back, between Brussels and Antwerp, he and Sir Peter Carew were seized (15 May) by order of Philip II of Spain, taken to England, and imprisoned in the Tower. Cheke was visited by two priests and by Dr John Feckenham, dean of St Paul's, whom he had formerly tried to convert to Protestantism, and, terrified by the prospect of being burned at the stake, he agreed to be received into the Church of Rome by Cardinal Pole. Overcome with shame, he did not long survive, but died in London, carrying, as Thomas Fuller says, "God's pardon and all good men's pity along with him."

Thomas Wilson, in the epistle prefixed to his translation of the Olynthiacs of Demosthenes (1570), has a long and most interesting eulogy of Cheke; and Thomas Nash, in To the Gentlemen Students, prefixed to Robert Greene's Menaphon (1589), calls him "the Exchequer of eloquence, Sir John Cheke, a man of men, supernaturally traded in all tongues." Many of Cheke's works are still in manuscript, some have been altogether lost. One of the most interesting from a historical point of view is the Hurt of Sedition how greneous it is to a Communeweith (1549), written on the occasion of Ket's rebellion, republished in 1569, 1576 and 1641, on the last occasion with a life of the author by Gerard Langbaine. Others are D. Joannis Chrysostomi homiliae duae (1543, the first entire Greek book known to have been printed in England), D. Joannis Chrysostomi de providentia Dei (1545), The Gospel according to St Matthew translated (c. 1550; ed. James Goodwin, 1843), De obitu Martini Buceri (1551), (Pope Leo VI's) de Apparatu bellico (Basel, 1554; but dedicated to Henry VIII, 1544), Carmen Heroicum, aut epithium in Antonium Dencium (1551), De pronuntiatione Graecae ... linguae (Basel, 1555). He also translated several Greek works, and lectured admirably upon Demosthenes.