John Joseph of Austria or John of Austria (the Younger) (Spanish: Don Juan José de Austria; 7 April 1629 – 17 September 1679) was a Spanish general and political figure. He was the only illegitimate son of Philip IV of Spain to be acknowledged by the King and trained for military command and political administration.
Don John advanced the causes of the Spanish Crown militarily and diplomatically during the century's crisis, recovering control of Naples, Sicily and Catalonia from local revolts, although failing to advance from only initial victories against France and England in his stint as governor of the Spanish Netherlands from 1656 to 1659. He then failed to quell the revolt of Portugal, which separated from Spain forever.