Pieter Gillis (28 July 1486 – 6 or 11 November 1533), known by his anglicised name Peter Giles, the gallicized Pierre Gilles and sometimes the Latinised Petrus Ægidius, was a humanist, printer, and secretary to the city of Antwerp in the early sixteenth century. He is most famous as a friend and supporter of Desiderius Erasmus and Thomas More. He seemed to have recommended the painter Hans Holbein the Younger to the court of England, where Thomas More received him delighted.

Thomas More's Utopia, although fictional, includes Pieter Gillis as a character in Book I. More dedicated Utopia to Gillis, who may have designed the Utopian alphabet. They first met when diplomatic business brought More and Cuthbert Tunstall to Antwerp.