John of Eltham, Earl of Cornwall was the son of Edward II of England and Isabella of France.

He was born on August 25, 1316 at Eltham Palace, Kent and was created Earl of Cornwall on 6 October 1328. He was due to marry Maria, daughter of Ferdinand IV of Castile, but he died, aged 20, at Perth, Scotland, before the marriage could take place. It is suggested that he was killed by his brother Edward III in a quarrel. He was buried in January 1337 at Westminster Abbey, London.