John Gwynneth (or Guinete) (fl. 1511–1557), was a clergyman of Welsh nationality originating from Gwynedd, and was a composer of religious and liturgical vocal music for which he was awarded a doctorate in the University of Oxford. He held benefices in England in Northamptonshire, Bedfordshire and London, and in North Wales at Clynnog Fawr. Although he was a polemicist for the Catholic faith, he maintained his ministry through the reigns of Henry VIII, Edward VI and Queen Mary, and was brother-in-law and executor of Stephen Vaughan (a supporter of the English Reformation). He is principally remembered, from the age of Thomas Tallis, as one of the other exponents of early Tudor period polyphony.