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 at Naples, Sicily, Catalonia, the Netherlands, Portugal, Dunkirk, and other fronts. He was the governor of the Southern Netherlands from 1656 to 1659. He remained a popular hero even as the fortunes of Imperial Spain began to decline. His feuds with his father's widow, Queen Mariana of Austria, led to a 1677 palace coup through which he exiled Mariana and took control of the monarchy of his half-brother Charles II of Spain. However, he proved far from the saviour Spain had hoped he would be. He remained in power until his death in 1679.

Philip IV, also called the Planet King, was King of Spain from 1621 to his death and King of Portugal from 1621 to 1640. Philip is remembered for his patronage of the arts, including such artists as Diego Velázquez, and his rule over Spain during the Thirty Years' War.