Gaston Jean-Baptiste, duc d'Orléans (April 25, 1608 - February 2, 1660), third son of the French king Henry IV, and his wife Marie de Medici, was born at Fontainebleau.

Known at first as the duke of Anjou, he was created duke of Orléans in 1626, and was nominally in command of the army which besieged La Rochelle in 1628, having already entered upon that course of political intrigue which was destined to occupy the remainder of his life. On two occasions he was obliged to leave France for conspiring against the government of his mother and of Cardinal Richelieu; and after waging an unsuccessful war in Languedoc, he took refuge in Flanders. Reconciled with his brother Louis XIII, he plotted against Richelieu in 1635, fled from the country, and then submitted to the king and the cardinal.

Soon afterwards the same process was repeated. Orleans stirred up Cinq-Mars to attempt Richelieu's murder, and then deserted his unfortunate accomplice. In 1643, on the death of Louis XIII, Gaston became lieutenant-general of the kingdom, and fought against Spain on the northern frontiers of France; but during the wars of the Fronde he passed with great facility from one party to the other. Then exiled by Mazarin to Blois in 1652 he remained there until his death.

Gaston's first wife was Marie (d. 1627), daughter and heiress of Henri de Bourbon, duc de Montpensier (d. 1608), and his second wife was Marguerite (d. 1672), sister of Charles III, Duke of Lorraine. By Marie he left a daughter, Anne, Duchess of Montpensier (La Grand Mademoiselle); and by Marguerite he left three daughters, Marguerite Louise (1645-1721), wife of Cosimo III, grand duke of Tuscany ; Elizabeth (1646-1696), wife of Louis Joseph, Duke of Guise ; and Françoise Madeleine (1648-1664), wife of Charles Emmanuel II of Savoy.