Robert Catesby (born in or after 1572, died 8 November 1605) was the leader of a group of provincial English Catholics who planned the failed Gunpowder Plot of 1605.
The Protestant James I, who became King of England in 1603, was less tolerant of Catholicism than his followers had hoped. Catesby therefore planned to kill him by blowing up the House of Lords with gunpowder during the State Opening of Parliament, the prelude to a popular revolt during which a Catholic monarch would be restored to the English throne. Early in 1604 he began to recruit other Catholics to his cause, including Thomas Wintour, John Wright, Thomas Percy, and Guy Fawkes. Described latterly as a charismatic and influential man, as well as a religious zealot, over the following months he helped to bring a further eight conspirators into the plot, whose naissance was planned for 5 November 1605. A letter sent anonymously to William Parker, 4th Baron Monteagle, alerted the authorities, and on the eve of the planned explosion, during a search of Parliament, Fawkes was found guarding the barrels of gunpowder. News of his arrest caused the other plotters to flee London, warning Catesby along their way.
With a much-diminished group of followers, Catesby made a stand at Holbeche House in Staffordshire, against a 200-strong company of armed men. He was shot and later found dead, clutching a picture of the Virgin Mary. As a warning to others, his body was exhumed and his head exhibited outside Parliament.