Pier Luigi Farnese, Duke of Parma (d. 1547)
Pier Luigi Farnese (19 November 1503 – 10 September 1547) was the first Duke of Castro from 1537 to 1545 and the first Duke of Parma and Piacenza from 1545 to 1547.

Born in Rome, Pier Luigi was the illegitimate son of Cardinal Alessandro Farnese (who later became Pope Paul III). He became a soldier and participated in the sack of Rome in 1527.