Cuthbert Tunstall (otherwise spelt Tunstal or Tonstall; 1474 – 18 November 1559) was an English humanist, bishop, diplomat, administrator and royal adviser. He served as Bishop of Durham during the reigns of Henry VIII, Edward VI, Mary I and Elizabeth I.
Cuthbert Tunstall was born at Hackforth near Bedale in North Yorkshire in 1474, an illegitimate son of Thomas Tunstall of Thurland Castle in Lancashire, who was later an esquire of the body of Richard III. His parents' subsequent marriage legitimized him under canon and civil law, if not under common law. His legitimate half-brother, Brian Tunstall, the so-called "stainless knight," was killed at the Battle of Flodden in 1513. Sir Walter Scott mentions "stainless Tunstall's banner white" in Canto Six, line 790 of Marmion.
Nothing is known of Tunstall's early life, except that he spent two years as a kitchen boy in the household of Sir Thomas Holland, perhaps at Lynn, Norfolk. He was admitted to Balliol College, Oxford, around 1491, where he studied mathematics, theology, and law. Around 1496, he became a scholar of the King's Hall, Cambridge. He did not receive a degree from either Oxford or Cambridge; he graduated from the University of Padua in 1505 as a Doctor of Civil Law and a Doctor of Canon Law. At Padua, he studied under some of the leading humanists and became proficient in Greek and Hebrew.
William Warham, Archbishop of Canterbury, made Tunstall his chancellor on 25 August 1511, and shortly afterward, he appointed him rector of Harrow on the Hill. He became a canon of Lincoln in 1514, and archdeacon of Chester in 1515. Soon thereafter, he was employed on diplomatic business by King Henry VIII and Cardinal Wolsey. In 1515, Tunstall was sent to Flanders with Sir Thomas More. At Brussels, he met Erasmus as well, becoming the intimate friend of both scholars. In 1519, he was sent to Cologne; a visit to Worms (1520–21) gave him a sense of the significance held by the Lutheran movement and its literature.
Tunstall was made Master of the Rolls in 1516 and Dean of Salisbury in 1521.