Jean-Paul Marat (May 24, 1743 – July 13, 1793), was a Swiss-born scientist and physician, who made much of his career in England, but is best known as a French Revolutionary. A member of the radical Jacobin faction during the French Revolution, he helped to launch the Reign of Terror.

From a relatively early date, Marat advocated doing away with the monarchy and raged against more moderate revolutionary leaders. In July 1790 he wrote "Five or six hundred heads cut off would have assured your repose, freedom and happiness. A false humanity has held your arms and suspended your blows; because of this millions of your brothers will lose their lives." He approved of the September 1792 massacres of jailed "enemies of the Revolution" and established the "Committee of Surveillance" whose role was to root out antirevolutionaries. Marat composed the death lists from which the innocent and the guilty alike were executed. One of his victims may have been the chemist Antoine Lavoisier.

He was stabbed in his bathtub by Charlotte Corday in 1793. Mademoiselle Corday was a Girondin and her action provoked reprisals in which thousands of enemies of the Jacobins -- royalists and Girondins alike -- were executed on supposed charges of treason. Corday herself was guillotined on July 17, 1793 for the murder.