Osuna, Or Ossuna, Pedro Tellez Y Giroii, duke of, viceroy of Naples, born in Valladolid in 1579, died in 1624. He spent his childhood with his grandfather, who was viceroy in Naples, and subsequently attended the university of ISalamanca. His satirical disposition drove him from the court of Philip II. After the accession of Philip III. (1598) he married a daughter of the duke of Alcala and assumed the title of duke of Osuna. He was soon again expelled from the court, and was allowed to return only in 1607 through the influence of the duke of Lerma, and after having served with distinction in the army in Flanders. He now gained considerable influence, and became in 1611 viceroy of Sicily, and in 1616 of Naples. He opposed the claims of Venice to control the trade of the Mediterranean, and incurred the hostility of the clergy by various measures, especially by resisting the establishment of the inquisition in Naples. Being suspected of aiming to make himself absolute ruler in S. Italy with the aid of foreign powers, he was recalled in 1620, and immediately after the accession of Philip IV. put on his trial. Though not convicted, he was imprisoned in the castle of Almedas, and was said to have died by poison supplied by his wife.

His son became viceroy of Sicily, and the dukes of Osuna still possess great wealth.