Michelangelo Ricci (1619–1682) was an Italian mathematician and a Cardinal of the Roman Catholic Church.
Michelangelo Ricci was born on 30 January 1619 in Rome, then capital of the Papal States, to a family of low social standing that originated in Bergamo.
He studied theology and law in Rome, where he was a contemporary of René-François de Sluse. He also studied mathematics under Benedetto Castelli who himself had been a student of Galileo Galilei. He was a friend of Evangelista Torricelli, kept close links with contemporary scientific culture, and played an important role in the development of the Galilean school.
Like de Sluze, he spent his entire career in the Roman Catholic Church and served the pope in various roles on several occasions. A trained theologian, he acted as consultant to various Congregations of the Roman Curia. Having suffered from epilepsy since his birth, he was (according to canon law of the time) disqualified from ordination. Nonetheless, he was created a Cardinal-Deacon in the Consistory of 1 September 1681 by Pope Innocent XI, with the title 'Cardinal-Deacon of Santa Maria in Aquiro'. His position in the church was very useful for protecting his friends and fellow scientists in their controversies with the opposing scholastic school.