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, but he graduated from the University of Padua in 1505 with 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.