Margaret of Parma (28 December 1522 - 18 January 1586), duchess of Parma and regent of the Netherlands from 1559 to 1567, was the illegitimate daughter of Charles V.

Her mother, Johanna Maria von der Gheest , a servant of Charles de Lalaing, Seigneur de Montigny, was a Fleming. Margaret was brought up by the Douwrin family, and later by her great-aunt Margaret of Austria and her aunt Maria of Hungary , who were successively regents of the Netherlands from 1507 to 1530 and from 1530 to 1555. In 1527, at the age of seven, she became engaged to the Pope's nephew, Alexander de Medici, duke of Florence. In 1533 she was acknowledged by her father and allowed to assume the name Margaret of Austria. On 29 February 1536 she married her betrothed, who was assassinated in 1537. On 4 November 1538 she became the wife of Ottavio Farnese, duke of Parma, the grandson of Pope Paul III. He was thirteen years old, she sixteen. The union, which proved an unhappy one, produced twin sons, one of whom died in infancy.

Like her aunts, who had trained her, Margaret was a woman of masculine abilities, and Philip II, when he left the Netherlands in 1559 for Spain, acted wisely in appointing her regent. In ordinary times she would probably have proved as successful a ruler as her two predecessors in that post, but her task was very different from theirs. She had to face the rising storm of discontent against the Inquisition and Spanish despotism, and Philip left her but nominal authority. He was determined to pursue his own arbitrary course, and the issue was the revolt of the Netherlands.

In 1567 Margaret resigned her post into the hands of the duke of Alva and retired to Italy. She had the satisfaction of seeing her son Alexander Farnese appointed to the office she had laid down, and to watch his successful career as governor-general of the Netherlands. She died at Ortona in 1586.