Guido Bentivoglio d'Aragona (4 October 1579 – 7 September 1644) was an Italian cardinal, and historian.
A member of the Ferrara branch of the influential Bentivoglio family of Bologna, he was the younger son of marchese Cornelio Bentivoglio and Isabella Bendidio. After studying at the universities of Ferrara and Padua, where in 1598 he received a doctorate utroque jure— in both civil and canon law— he returned to Ferrara, to the humanistic studies that honed his elegant writing style. There Pope Clement VIII, on a visit to the city that had recently fallen under direct papal control, made him his private chamberlain, and he returned with Clement to Rome.
Under Clement's successor, Pope Paul V, he was appointed titular archbishop of Rhodes, 14 May 1607, with a dispensation for being three months shy of the canonical age and not having yet received the sacred orders, in order to give him appropriate credentials as nuncio at the court of the Archdukes Albert and Isabella in the Habsburg Netherlands, (1 June 1607 – 24 October 1615).
He arrived in Brussels when negotiations between the Habsburgs and the Dutch Republic to end the Eighty Years' War were about to begin. Following the conclusion of the Twelve Years' Truce in April 1609, he was greatly concerned with the position of Catholicism in the Republic. Accredited to a Habsburg court, he likewise took a keen interest in the final stages of the reign and the succession of Emperor Rudolf II. Three more topics occupied a great deal of his time: the struggle over the Jülich-Cleves inheritance, which was set to ignite the Thirty Years War, the flight of the prince de Condé from France in objection to Henri IV's divorce and remarriage, and the degree of toleration for Catholics in England and Ireland under James I. His correspondence reveals Bentivoglio as "the skilled diplomatist, polished by constant intercourse with the most refined society, as well as the mature observer," according to Ludwig Pastor.