John of Gloucester (or John of Pontefract) (c. 1468 – c. 1499 (based on historical hypothesis)) was an illegitimate son of King Richard III of England. John is so called because his father was Duke of Gloucester at the time of his birth. His father appointed him Captain of Calais, a position he lost after his father's death. He seems to have been held in custody at some point during the reign of Henry VII and may have been executed around 1499.