James fitz Maurice FitzGerald (died 1579), called "fitz Maurice", was an Irishrebel who led the First Desmond rebellion and the Second Desmond rebellion, he was the captain-general of Desmond while Gerald FitzGerald, 14th Earl of Desmond, was detained in England by Queen Elizabeth after the Battle of Affane in 1565.
Outraged by the religious persecution of the Catholic Church in Ireland, Fitzmaurice led the first Desmond Rebellion, intending to replace Queen Elizabeth with Don John of Austria of the House of Habsburg as the new High King of Ireland, in 1569 and was accordingly called the "Archtraitor" by the English. He surrendered in 1573, prostrating himself in Kilmallock church before John Perrot, president of Munster.