Margaret de Clare, Baroness Badlesmere (c.1 April 1287 – 22 October 1333 / 3 January 1334) was a Norman-Irish noblewoman, suo jure heiress, and the wife of Bartholomew de Badlesmere, 1st Baron Badlesmere.
She was arrested and subsequently imprisoned in the Tower of London for the duration of a year from November 1321 to November 1322, making her the first female prisoner in the Tower's history. She was jailed on account of having ordered an
armed assault on Isabella of France, Queen consort of King Edward II of England. Before Margaret had instructed her archers to fire upon Isabella and her escort, she had refused the Queen admittance to Leeds Castle where her husband, Baron
Badlesmere held the post of governor, but which was legally the property of Queen Isabella as part of the latter's dowry. Margaret surrendered the castle on 31 October 1321 after it was besieged by the King's forces using ballistas. Edward's capture of Leeds Castle was the catalyst which led to the Despenser War in the Welsh Marches and the north of England.
Upon her release from the Tower, Margaret entered a religious life at the convent house of the Minorite Sisters outside Aldgate. King Edward granted her a stipend to pay for her maintenance.