Here is a list of Catholic priests, brothers, bishops, abbots, cardinals, popes (and, in at least four cases, saints) who have made major contributions to science.

Men of the Church and Men of Science

Fr. José de Acosta (1539–1600) – Jesuit missionary and naturalist who wrote one of the first detailed and realistic descriptions of the New World

Fr. François d'Aguilon (1567–1617) – Belgian Jesuit mathematician, physicist and architect

Fr. Lorenzo Albacete (1941–2014) – priest, physicist and theologian

Fr. Albert of Castile (c. 1460-1522) - Dominican priest and historian

Bishop Albert of Saxony (philosopher) (c. 1320–1390) – German bishop who wrote on logic and physics; with Buridan he helped develop the theory that was a precursor to the modern theory of inertia

St. Albertus Magnus (c. 1206–1280) – Dominican friar and Bishop of Regensberg who has been described as "one of the most famous precursors of modern science in the High Middle Ages." Patron Saint of Natural Sciences; Works in physics, logic, metaphysics, biology and psychology.

Fr. Giulio Alenio (1582–1649) – Jesuit theologian, astronomer and mathematician; was sent to the Far East as a missionary and adopted a Chinese name and customs; wrote 25 books, including a cosmography and a Life of Jesus in Chinese.

Fr. José María Algué (1856–1930) – priest and meteorologist who invented the barocyclonometer

Fr. José Antonio de Alzate y Ramírez (1737–1799) – priest, scientist, historian, cartographer and meteorologist who wrote more than thirty treatises on a variety of scientific subjects
Fr. Francesco Castracane degli Antelminelli (1817–1899) – priest and botanist who was one of the first to introduce microphotography into the study of biology

Fr. Giovanni Antonelli (1818–1872) – priest and director of the Ximenian Observatory of Florence who also collaborated on the design of a prototype of the internal combustion engine

Fr. Nicolò Arrighetti (1709–1767) – Jesuit who wrote treatises on light, heat and electricity

Fr. Mariano Artigas (1938–2006) – Spanish physicist, philosopher and theologian who received the Templeton Foundation Prize in 1995

Fr. Giuseppe Asclepi (1706–1776) – Jesuit astronomer and physician who served as director of the Collegio Romano observatory; the lunar crater Asclepi is named after him

Fr. Nicanor Pier Giorgio Austriaco, O.P., Ph.D., S.T.D., Professor of Biology and of Theology at Providence College

Fr. Roger Bacon (c. 1214–1294) – Franciscan friar who made significant contributions to mathematics and optics and has been described as the Father of Modern Scientific Method

Abbot Bernardino Baldi (1533–1617) – abbot, mathematician and writer

Fr. Eugenio Barsanti (1821–1864) – Piarist, possible inventor of the internal combustion engine

Fr. Bartholomeus Amicus (1562–1649) – Jesuit, wrote on philosophy, mathematics, astronomy and the concept of vacuum and its relationship with God

Fr. Daniello Bartoli (1608–1685) – Bartoli and fellow Jesuit astronomer Niccolò Zucchi are credited as probably having been the first to see the equatorial belts on the planet Jupiter

Fr. Joseph Bayma (1816–1892) – Jesuit known for work in stereochemistry and mathematics

Fr. Giacopo Belgrado (1704–1789) – Jesuit professor of mathematics and physics and court mathematician who did experimental work in physics

Fr. Mario Bettinus (1582–1657) – Jesuit philosopher, mathematician and astronomer; lunar crater Bettinus named after him

Fr. Giuseppe Biancani (1566–1624) – Jesuit astronomer, mathematician and selenographer, after whom the lunar crater Blancanus is named

Fr. Jacques de Billy (1602–1679) – Jesuit who has produced a number of results in number theory which have been named after him; published several astronomical tables; the lunar crater Billy is named after him

Fr. Paolo Boccone (1633–1704) – Cistercian botanist who contributed to the fields of medicine and toxicology

Fr. Bernard Bolzano (1781–1848) – priest, mathematician and logician whose other interests included metaphysics, ideas, sensation and truth

Fr. Anselmus de Boodt (1550–1632) – priest who was one of the founders of mineralogy

Fr. Theodoric Borgognoni (1205–1298) – Dominican friar, Bishop of Cervia and medieval Surgeon who made important contributions to antiseptic practice and anesthetics

Fr. Christopher Borrus (1583–1632) – Jesuit mathematician and astronomy who made observations on the magnetic variation of the compass

Fr. Roger Joseph Boscovich (1711–1787) – Jesuit polymath known for his contributions to modern atomic theory and astronomy

Fr. Joachim Bouvet (1656–1730) – Jesuit sinologist and cartographer who did his work in China

Fr. Michał Boym (c. 1612–1659) – Jesuit who was one of the first westerners to travel within the Chinese mainland and the author of numerous works on Asian fauna, flora and geography

Fr. Thomas Bradwardine (c. 1290–1349) – Archbishop of Canterbury and mathematician who helped develop the mean speed theorem; one of the Oxford Calculators

Fr. Martin Stanislaus Brennan (1845–1927) – priest and astronomer who wrote several books about science

Fr. Henri Breuil (1877–1961) – priest, archaeologist, anthropologist, ethnologist and geologist

Fr. Jan Brożek (1585–1652) – Polish priest, polymath, mathematician, astronomer and physician; the most prominent Polish mathematician of the 17th century

Fr. Louis-Ovide Brunet (1826–1876) – priest, one of the founding fathers of Canadian botany

Bl. Francesco Faà di Bruno (c. 1825–1888) – priest and mathematician beatified by Pope John Paul II

Fr. Ismaël Bullialdus (1605–1694) – priest, astronomer and member of the Royal Society; the Bullialdus crater is named in his honor

Fr. Jean Buridan (c. 1300 – after 1358) – priest who formulated early ideas of momentum and inertial motion and sowed the seeds of the Copernican revolution in Europe

Fr. Roberto Busa (1913–2011) – Jesuit, wrote a lemmatization of the complete works of St. Thomas Aquinas (Index Thomisticus) which was later digitalized by IBM. Fr. Busa is the impetus for the use of alphabet, including search engines on computers and, later, the Net

Fr. Niccolò Cabeo (1586–1650) – Jesuit mathematician; the crater Cabeus is named in his honor

Fr. Nicholas Callan (1799–1846) – priest and Irish scientist best known for his work on the induction coil

Fr. John Cantius (1390–1473) – priest and Buridanist mathematical physicist who further developed the theory of impetus

Fr. Jean Baptiste Carnoy (1836–1899) – priest, has been called the Founder of the Science of Cytology

Fr. Giovanni di Casali (d. c. 1375) – Franciscan friar who provided a graphical analysis of the motion of accelerated bodies

Fr. Paolo Casati (1617–1707) – Jesuit mathematician who wrote on astronomy and vacuums; the lunar crater Casatus is named after him

Fr. Laurent Cassegrain (1629–1693) – priest who was the probable namesake of the Cassegrain telescope; the lunar crater Cassegrain is named after him

Fr. Benedetto Castelli (1578–1643) – Benedictine mathematician; long-time friend and supporter of Galileo Galilei, who was his teacher; wrote an important work on fluids in motion

Fr. Bonaventura Cavalieri (1598–1647) – Jesuate priest (not to be confused with Jesuit) known for his work on the problems of optics and motion, work on the precursors of infinitesimal calculus and the introduction of logarithms to Italy; his principle in geometry partially anticipated integral calculus; the lunar crater Cavalerius is named in his honor

Fr. Antonio José Cavanilles (1745–1804) – priest and leading Spanish taxonomic botanist of the 18th century

Fr. Francesco Cetti (1726–1778) – Jesuit zoologist and mathematician

Fr. Tommaso Ceva (1648–1737) – Jesuit mathematician and professor who wrote treatises on geometry, gravity and arithmetic

Fr. Christopher Clavius (1538–1612) –Jesuit astronomer and mathematician who headed the commission that yielded the Gregorian calendar; wrote influential astronomical textbook

Br. Guy Consolmagno (1952–) – Jesuit astronomer and planetary scientist

Fr. Nicolaus Copernicus (1473–1543) – Renaissance astronomer and priest famous for his heliocentric cosmology that set in motion the Copernican Revolution

Fr. Vincenzo Coronelli (1650–1718) – Franciscan cosmographer, cartographer, encyclopedist and globe-maker

Fr. George Coyne (1933–) – Jesuit astronomer and former director of the Vatican Observatory

Fr. James Cullen (mathematician) (1867–1933) – Jesuit mathematician who published what is now known as Cullen numbers in number theory

Fr. James Curley (astronomer) (1796–1889) – Jesuit, first director of Georgetown Observatory and determined the latitude and longitude of Washington, D.C.

Fr. Albert Curtz (1600–1671) – Jesuit astronomer who expanded on the works of Tycho Brahe and contributed to early understanding of the moon; the lunar crater Curtius is named after him

Fr. Johann Baptist Cysat (1587–1657) – Jesuit mathematician and astronomer, after whom the lunar crater Cysatus is named; published the first printed European book concerning Japan; one of the first to make use of the newly developed telescope; most important work was on comets

Fr. Jean-Baptiste Chappe d'Auteroche (1722–1769) – priest and astronomer best known for his observations of the transits of Venus

Fr. Ignazio Danti (1536–1586) – Dominican mathematician, astronomer, cosmographer and cartographer

Fr. Armand David (1826–1900) – Lazarist priest, zoologist and botanist who did important work in these fields in China

Fr. Francesco Denza (1834–1894) – Barnabite meteorologist, astronomer and director of Vatican Observatory

Fr. Václav Prokop Diviš (1698–1765) – Czech priest who studied electrical phenomena and constructed, among other inventions, the first electrified musical instrument in history

Fr. Alberto Dou (1915–2009) – Spanish Jesuit priest who was president of the Royal Society of Mathematics, member of the Royal Academy of Natural, Physical and Exact Sciences and one of the foremost mathematicians of his country

Fr. Johann Dzierzon (1811–1906) – priest and pioneering apiarist who discovered the phenomenon of parthenogenesis among bees and designed the first successful movable-frame beehive; has been described as the "Father of modern apiculture"

Fr. Honoré Fabri (1607–1688) – Jesuit mathematician and physicist

Fr. Jean-Charles de la Faille (1597–1652) – Jesuit mathematician who determined the center of gravity of the sector of a circle for the first time

Fr. Gabriele Falloppio (1523–1562) – priest and one of the most important anatomists and physicians of the sixteenth century; the Fallopian tubes, which extend from the uterus to the ovaries, are named for him

Fr. Gyula Fényi (1845–1927) – Jesuit astronomer and director of the Haynald Observatory; noted for his observations of the sun; the lunar crater Fényi is named after him

Fr. Louis Feuillée (1660–1732) – Minim explorer, astronomer, geographer and botanist
Placidus Fixlmillner (1721–1791) – Benedictine priest and one of the first astronomers to compute the orbit of Uranus

Fr. Paolo Frisi (1728–1784) – priest, mathematician and astronomer who did significant work in hydraulics

Fr. José Gabriel Funes (1963– ) – Jesuit astronomer and current director of the Vatican Observatory

Fr. Lorenzo Fazzini (1787–1837) – priest and physicist born in Vieste and working in Naples

Fr. Joseph Galien (1699 – c. 1762) – Dominican professor who wrote on aeronautics, hailstorms and airships

Abbot Jean Gallois (1632–1707) – French scholar, abbot and member of Academie des sciences

Fr. Pierre Gassendi (1592–1655) – French priest, astronomer and mathematician who published the first data on the transit of Mercury; best known intellectual project attempted to reconcile Epicurean atomism with Christianity

Fr. Agostino Gemelli (1878–1959) – Franciscan physician and psychologist; founded Catholic University of the Sacred Heart in Milan

Fr. Johannes von Gmunden (c. 1380–1442) – Priest, mathematician and astronomer who compiled astronomical tables; Asteroid 15955 Johannesgmunden named in his honor

Fr. Carlos de Sigüenza y Góngora (1645–1700) – priest, polymath, mathematician, astronomer and cartographer; drew the first map of all of New Spain

Fr. Andrew Gordon (Benedictine) (1712–1751) – Benedictine monk, physicist and inventor who made the first electric motor

Fr. Christoph Grienberger (1561–1636) – Jesuit astronomer after whom the lunar crater Gruemberger is named; verified Galileo's discovery of Jupiter's moons.

Fr. Francesco Maria Grimaldi (1618–1663) – Jesuit who discovered the diffraction of light (indeed coined the term "diffraction"), investigated the free fall of objects and built and used instruments to measure lunar geological features

Fr. Robert Grosseteste (c. 1175 – 1253) – bishop who was one of the most knowledgeable men of the Middle Ages; has been called "the first man ever to write down a complete set of steps for performing a scientific experiment"

Fr. Paul Guldin (1577–1643) – Jesuit mathematician and astronomer who discovered the Guldinus theorem to determine the surface and the volume of a solid of revolution

Fr. Bartolomeu de Gusmão (1685–1724) – Jesuit known for his early work on lighter-than-air airship design

Fr. Johann Georg Hagen (1847–1930) – Jesuit director of the Georgetown and Vatican Observatories; the lunar crater Hagen is named after him
Abbot Nicholas Halma (1755–1828) – French abbot, mathematician and translator

Fr. Jean-Baptiste du Hamel (1624–1706) – French priest, natural philosopher and secretary of the Academie Royale des Sciences

Fr. René Just Haüy (1743–1822) – priest known as the Father of Crystallography

Fr. Maximilian Hell (1720–1792) – Jesuit astronomer and director of the Vienna Observatory; the lunar crater Hell is named after him

Fr. Michał Heller (1936– ) – Polish priest, Templeton Prize winner and prolific writer on numerous scientific topics

Fr. Lorenz Hengler (1806–1858) – priest often credited as the inventor of the horizontal pendulum

Fr. Hermann of Reichenau (1013–1054) – Benedictine historian, music theorist, astronomer and mathematician

Fr. Pierre Marie Heude (1836–1902) – Jesuit missionary and zoologist who studied the natural history of Eastern Asia

Fr. Franz von Paula Hladnik (1773–1844) – priest and botanist who discovered several new kinds of plants and certain genera have been named after him

Fr. Giovanni Battista Hodierna (1597–1660) – priest and astronomer who catalogued nebulous objects and developed an early microscope

Fr. Victor-Alphonse Huard (1853–1929) – priest, naturalist, educator, writer and promoter of the natural sciences

Fr. Maximus von Imhof (1758–1817) – German Augustinian physicist and director of the Munich Academy of Sciences

Fr. Giovanni Inghirami (1779–1851) – Italian Piarist astronomer who has a lunar valley named after him as well as a crater

Fr. François Jacquier (1711–1788) – Franciscan mathematician and physicist; at his death he was connected with nearly all the great scientific and literary societies of Europe

Fr. Stanley Jaki (1924–2009) – Benedictine priest and prolific writer who wrote on the relationship between science and theology

Fr. Ányos Jedlik (1800–1895) – Benedictine engineer, physicist and inventor; considered by Hungarians and Slovaks to be the unsung Father of the dynamo and electric motor

Fr. Georg Joseph Kamel (1661–1706) – Jesuit missionary and botanist who established the first pharmacy in the Philippines

Fr. Karl Kehrle (1898–1996) – Benedictine Monk of Buckfast Abbey, England; beekeeper; world authority on bee breeding, developer of the Buckfast bee which is the hybrid commonly used currently

Fr. Eusebio Kino (1645–1711) – Jesuit missionary, mathematician, astronomer and cartographer; drew maps based on his explorations first showing that California was not an island, as then believed; published an astronomical treatise in Mexico City of his observations of the Kirsch comet

Fr. Otto Kippes (1905–1994) – priest acknowledged for his work in asteroid orbit calculations; the main belt asteroid 1780 Kippes was named in his honor

Fr. Athanasius Kircher (1602–1680) – Jesuit who has been called the Father of Egyptology and "Master of a hundred arts"; wrote an encyclopedia of China; one of the first people to observe microbes through a microscope

Fr. Wenceslas Pantaleon Kirwitzer (1588–1626) – Jesuit astronomer and missionary who published observations of comets

Fr. Jan Krzysztof Kluk (1739–1796) – priest, naturalist agronomist and entomologist who wrote a multi-volume work on Polish animal life

Fr. Marian Wolfgang Koller (1792–1866) – Benedictine professor who wrote on astronomy, physics and meteorology

Fr. Franz Xaver Kugler (1862–1929) – Jesuit chemist, mathematician and Assyriologist who is most noted for his studies of cuneiform tablets and Babylonian astronomy

Bl. Ramon Llull (ca. 1232 – ca. 1315) Majorcan writer and philosopher, logician and a Franciscan tertiary considered a pioneer of computation theory. Created the world's first analog computer

Fr. Nicolas Louis de Lacaille (1713–1762) – French deacon and astronomer noted for cataloguing stars, nebulous objects and constellations

Fr. Eugene Lafont (1837–1908) – Jesuit physicist, astronomer and founder of the first Scientific Society in India

Fr. Antoine de Laloubère (1600–1664) – Jesuit and first mathematician to study the properties of the helix

Fr. Bernard Lamy (1640–1715) – Oratorian philosopher and mathematician who wrote on the parallelogram of forces

Fr. Pierre André Latreille (1762–1833) – priest and entomologist whose works describing insects assigned many of the insect taxa still in use today

Abbot Georges Lemaître (1894–1966) – Belgian priest and Father of the Big Bang Theory

Fr. Thomas Linacre (c. 1460–1524) – English priest, humanist, translator and physician

Fr. Francis Line (1595–1675) – Jesuit magnetic clock and sundial maker who disagreed with some of the findings of Newton and Boyle

Fr. Juan Caramuel y Lobkowitz (1606–1682) – Cistercian who wrote on a variety of scientific subjects, including probability theory

Fr. Jean Mabillon (1632–1707) – Benedictine monk and scholar, considered the founder of paleography and diplomatics

Fr. James B. Macelwane (1883–1956) – "the best-known Jesuit seismologist" and "one of the most honored practitioners of the science of all time"; wrote the first textbook on seismology in America

Fr. John MacEnery (1797–1841) – archaeologist who investigated the Palaeolithic remains at Kents Cavern

Fr. Paul McNally (1890–1955) – Jesuit astronomer and director of Georgetown Observatory; the lunar crater McNally is named after him

Fr. Manuel Magri (1851–1907) – Jesuit ethnographer, archaeologist and writer; one of Malta's pioneers in archaeology

Fr. Emmanuel Maignan (1601–1676) – Minim physicist and professor of medicine who published works on gnomonics and perspective

Fr. Charles Malapert (1581–1630) – Jesuit writer, astronomer and proponent of Aristotelian cosmology; also known for observations of sunpots and of the lunar surface and the lunar crater Malapert is named after him

Fr. Nicolas Malebranche (1638–1715) – Oratorian philosopher who studied physics, optics and the laws of motion and disseminated the ideas of Descartes and Leibniz

Fr. Marcin of Urzędów (c. 1500–1573) – priest, physician, pharmacist and botanist

Fr. Joseph Maréchal (1878–1944) – Jesuit philosopher and psychologist

Fr. Marie-Victorin (1885–1944) – Christian Brother and botanist best known as the Father of the Jardin Botanique de Montréal

Fr. Edme Mariotte (c. 1620–1684) – priest and physicist who recognized Boyle's Law and wrote about the nature of color

Fr. Francesco Maurolico (1494–1575) – Benedictine who made contributions to the fields of geometry, optics, conics, mechanics, music and astronomy and gave the first known proof by mathematical induction

Fr. Christian Mayer (astronomer) (1719–1783) – Jesuit astronomer most noted for pioneering the study of binary stars

Fr. James Robert McConnell (1915–1999) – Irish theoretical physicist, pontifical academician, Monsignor

Fr. Gregor Mendel (1822–1884) – Augustinian monk and Father of genetics

Fr. Pietro Mengoli (1626–1686) – priest and mathematician who first posed the famous Basel Problem

Fr. Giuseppe Mercalli (1850–1914) – priest, volcanologist and director of the Vesuvius Observatory who is best remembered today for his Mercalli scale for measuring earthquakes which is still in use

Fr. Marin Mersenne (1588–1648) – Minim philosopher, mathematician and music theorist who is often referred to as the "Father of acoustics"

Fr. Paul of Middelburg (1446–1534) – Bishop of Fossombrone who wrote important works on the reform of the calendar

Fr. Maciej Miechowita (1457–1523) – priest who wrote the first accurate geographical and ethnographical description of Eastern Europe, as well as two medical treatises

Fr. François-Napoléon-Marie Moigno (1804–1884) – Jesuit physicist and mathematician; was an expositor of science and translator rather than an original investigator

Fr. Juan Ignacio Molina (1740–1829) – Jesuit naturalist, historian, botanist, ornithologist and geographer

Fr. Louis Moréri (1643–1680) – 17th-century priest and encyclopedist

Fr. Théodore Moret (1602–1667) – Jesuit mathematician and author of the first mathematical dissertations ever defended in Prague; the lunar crater Moretus is named after him

Fr. Landell de Moura (1861–1928) – priest and inventor who was the first to accomplish the transmission of the human voice by a wireless machine

Abbot Gabriel Mouton (1618–1694) – abbot, mathematician, astronomer and early proponent of the metric system

Fr. Jozef Murgaš (1864–1929) – priest who contributed to wireless telegraphy and help develop mobile communications and wireless transmission of information and human voice

Fr. José Celestino Mutis (1732–1808) – Priest, botanist and mathematician who led the Royal Botanical Expedition of the New World

Fr. Jean François Niceron (1613–1646) – Minim mathematician who studied geometrical optics

Cardinal Nicholas of Cusa (1401–1464) – Cardinal, philosopher, jurist, mathematician, astronomer and one of the great geniuses and polymaths of the 15th century

Fr. Julius Nieuwland (1878–1936) – Holy Cross priest, known for his contributions to acetylene research and its use as the basis for one type of synthetic rubber, which eventually led to the invention of neoprene by DuPont

Abbot Jean-Antoine Nollet (1700–1770) – abbot and physicist who discovered the phenomenon of osmosis in natural membranes

Fr. Hugo Obermaier (1877–1946) – priest, prehistorian and anthropologist who is known for his work on the diffusion of mankind in Europe during the Ice Age, as well as his work with north Spanish cave art

Fr. William of Ockham (c. 1288 – c. 1348) – Franciscan Scholastic who wrote significant works on logic, physics and theology; known for Occam's razor-principle

Bishop Nicole Oresme (c. 1323–1382) – one of the most famous and influential philosophers of the later Middle Ages; economist, mathematician, physicist, astronomer, philosopher, theologian and Bishop of Lisieux and competent translator; one of the most original thinkers of the 14th century

Fr. Barnaba Oriani (1752–1832) – Barnabite geodesist, astronomer and scientist whose greatest achievement was his detailed research of the planet Uranus; also known for Oriani's Theorem

Fr. Tadeusz Pacholczyk (1965–) – priest, neuroscientist and writer

Fr. Luca Pacioli (c. 1446–1517) – Franciscan friar who published several works on mathematics; often regarded as the "Father of accounting"

Fr. Ignace-Gaston Pardies (1636–1673) – Jesuit physicist known for his correspondence with Newton and Descartes

Fr. Franciscus Patricius (1529–1597) – priest, cosmic theorist, philosopher and Renaissance scholar

Fr. John Peckham (1230–1292) – Archbishop of Canterbury and early practitioner of experimental science

Abbot Nicolas Claude Fabri de Peiresc (1580–1637) – abbot and astronomer who discovered the Orion Nebula; lunar crater Peirescius named in his honor

Fr. Stephen Joseph Perry (1833–1889) – Jesuit astronomer and Fellow of the Royal Society; made frequent observations of Jupiter's satellites, of stellar occultations, of comets, of meteorites, of sun spots and faculae

Fr. Giambattista Pianciani (1784–1862) – Jesuit mathematician and physicist

Fr. Giuseppe Piazzi (1746–1826) – Theatine mathematician and astronomer who discovered Ceres, today known as the largest member of the asteroid belt; also did important work cataloguing stars

Fr. Jean Picard (1620–1682) – priest and first person to measure the size of the Earth to a reasonable degree of accuracy; also developed what became the standard method for measuring the right ascension of a celestial object; the PICARD mission, an orbiting solar observatory, is named in his honor

Fr. Edward Pigot (1858–1929) – Jesuit seismologist and astronomer

Fr. Alexandre Guy Pingré (1711–1796) – French priest astronomer and naval geographer; the lunar crater Pingré is named after him, as is the asteroid 12719 Pingré

Fr. Andrew Pinsent (1966–) – priest whose current research includes the application of insights from autism and social cognition to 'second-person' accounts of moral perception and character formation; his previous scientific research contributed to the DELPHI experiment at CERN

Cardinal Jean Baptiste François Pitra (1812–1889) – Benedictine cardinal, archaeologist and theologian who noteworthy for his great archaeological discoveries

Fr. Charles Plumier (1646–1704) – Minim friar who is considered one of the most important botanical explorers of his time

Fr. Marcin Odlanicki Poczobutt (1728–1810) – Jesuit astronomer and mathematician; granted the title of the King's Astronomer; the lunar crater Poczobutt is named after him

Fr. Léon Abel Provancher (1820–1892) – priest and naturalist devoted to the study and description of the fauna and flora of Canada; his pioneer work won for him the appellation of the "Father of Canadian Natural History"

Fr. Louis Receveur (1757–1788) – Franciscan naturalist and astronomer; described as being as close as one could get to being an ecologist in the 18th century

Fr. Franz Reinzer (1661–1708) – Jesuit who wrote an in-depth meteorological, astrological and political compendium covering topics such as comets, meteors, lightning, winds, fossils, metals, bodies of water and subterranean treasures and secrets of the earth
Bishop Louis Rendu (1789–1859) – bishop who wrote an important book on the mechanisms of glacial motion; the Rendu Glacier, Alaska, US and Mount Rendu, Antarctica are named for him

Fr. Vincenzo Riccati (1707–1775) – Italian Jesuit mathematician and physicist

Fr. Matteo Ricci (1552–1610) – one of the founding fathers of the Jesuit China Mission and co-author of the first European-Chinese dictionary. (On route to being a saint)

Fr. Giovanni Battista Riccioli (1598–1671) – Jesuit astronomer who authored Almagestum novum, an influential encyclopedia of astronomy; the first person to measure the rate of acceleration of a freely falling body; created a selenograph with Father Grimaldi that now adorns the entrance at the National Air and Space Museum in Washington, D.C.
Abbot Richard of Wallingford (1292–1336) – abbot, renowned clockmaker and one of the initiators of western trigonometry

Fr. Johannes Ruysch (c. 1460–1533) – priest, explorer, cartographer and astronomer who created the second oldest known printed representation of the New World

Fr. Giovanni Girolamo Saccheri (1667–1733) – Jesuit mathematician and geometer

Fr. Johannes de Sacrobosco (c. 1195 – c. 1256) – Irish monk and astronomer who wrote the authoritative medieval astronomy text Tractatus de Sphaera; his Algorismus was the first text to introduce Hindu-Arabic numerals and procedures into the European university curriculum; the lunar crater Sacrobosco is named after him

Fr. Gregoire de Saint-Vincent (1584–1667) – Jesuit mathematician who made important contributions to the study of the hyperbola

Fr. Alphonse Antonio de Sarasa (1618–1667) – Jesuit mathematician who contributed to the understanding of logarithms

Fr. Christoph Scheiner (c. 1573–1650) – Jesuit physicist, astronomer and inventor of the pantograph; wrote on a wide range of scientific subjects
Fr. Wilhelm Schmidt (linguist) (1868–1954) – Austrian priest, linguist, anthropologist and ethnologist

Fr. George Schoener (1864–1941) – priest who became known in the United States as the "Padre of the Roses" for his experiments in rose breeding

Fr. Gaspar Schott (1608–1666) – Jesuit physicist, astronomer and natural philosopher who is most widely known for his works on hydraulic and mechanical instruments

Fr. Franz Paula von Schrank (1747–1835) – priest, botanist, entomologist and prolific writer

Fr. Berthold Schwarz (c. 14th century) – Franciscan friar and reputed inventor of gunpowder and firearms

Fr. Anton Maria Schyrleus of Rheita (1604–1660) – Capuchin astronomer and optrician who built Kepler's telescope

Fr. George Mary Searle (1839–1918) – Paulist astronomer and professor who discovered six galaxies

Fr. Angelo Secchi (1818–1878) – Jesuit pioneer in astronomical spectroscopy and one of the first scientists to state authoritatively that the sun is a star

Fr. Alessandro Serpieri (1823–1885) – priest, astronomer and seismologist who studied shooting stars and was the first to introduce the concept of the seismic radiant

Fr. Gerolamo Sersale (1584–1654) – Jesuit astronomer and selenographer; his map of the moon can be seen in the Naval Observatory of San Fernando; the lunar crater Sirsalis is named after him

Fr. Benedict Sestini (1816–1890) – Jesuit astronomer, mathematician and architect; studied sunspots and eclipses; wrote textbooks on a variety of mathematical subjects

Fr. René François Walter de Sluse (1622–1685) – Priest and mathematician with a family of curves named after him

Fr. Domingo de Soto (1494–1560) – Spanish Dominican priest and professor at the University of Salamanca; in his commentaries to Aristotle he proposed that free falling bodies undergo constant acceleration

Fr. Lazzaro Spallanzani (1729–1799) – priest, biologist and physiologist who made important contributions to the experimental study of bodily functions, animal reproduction and essentially discovered echolocation; his research of biogenesis paved the way for the investigations of Louis Pasteur

Fr. Valentin Stansel (1621–1705) – Jesuit astronomer who made important observations of comets

Fr. Johan Stein (1871–1951) – Jesuit astronomer and director of the Vatican Observatory, which he modernized and relocated to Castel Gandolfo; the crater Stein on the far side of the Moon is named after him

Bl. Nicolas Steno (1638–1686) – Bishop beatified by Pope John Paul II who is often called the Father of geology and stratigraphy, and is known for Steno's principles
Pope Sylvester II (c. 946–1003) – Prolific scholar who endorsed and promoted Arabic knowledge of arithmetic, mathematics and astronomy in Europe, reintroducing the abacus and armillary sphere which had been lost to Europe since the end of the Greco-Roman era

Fr. Alexius Sylvius Polonus (1593 – c. 1653) – Jesuit astronomer who studied sunspots and published a work on calendariography

Fr. Ignacije Szentmartony (1718–1793) – Jesuit cartographer, mathematician and astronomer who became a member of the expedition that worked on the rearrangement of the frontiers among colonies in South America

Fr. André Tacquet (1612–1660) – Jesuit mathematician whose work laid the groundwork for the eventual discovery of calculus

Fr. Pierre Teilhard de Chardin (1881–1955) – Jesuit paleontologist and geologist who took part in the discovery of Peking Man

Fr. Francesco Lana de Terzi (c. 1631–1687) – Jesuit referred to as the Father of Aviation for his pioneering efforts; he also developed a blind writing alphabet prior to Braille.

Fr. Theodoric of Freiberg (c. 1250 – c. 1310) – Dominican theologian and physicist who gave the first correct geometrical analysis of the rainbow

Fr. Joseph Tiefenthaler (1710–1785) – Jesuit who was one of the earliest European geographers to write about India

Fr. Giuseppe Toaldo (1719–1797) – priest and physicist who studied atmospheric electricity and did important work with lightning rods; the asteroid 23685 Toaldo is named for him

Fr. José Torrubia (c. 1700–1768) – Franciscan linguist, scientist, collector of fossils and books and writer on historical, political and religious subjects

Fr. Franz de Paula Triesnecker (1745–1817) – Jesuit astronomer and director of the Vienna Observatory; published a number of treatises on astronomy and geography; the lunar crater Triesnecker is named after him

Fr. Luca Valerio (1552–1618) – Jesuit mathematician who developed ways to find volumes and centers of gravity of solid bodies

Fr. Pierre Varignon (1654–1722) – priest and mathematician whose principle contributions were to statics and mechanics; created a mechanical explanation of gravitation

Fr. Jacques de Vaucanson (1709–1782) – French Minim friar inventor and artist who was responsible for the creation of impressive and innovative automata and machines such as the first completely automated loom

Fr. Giovanni Battista Venturi (1746–1822) – priest who discovered the Venturi effect

Bishop Fausto Veranzio (c. 1551–1617) – Bishop, polymath, inventor and lexicographer

Fr. Ferdinand Verbiest (1623–1688) – Jesuit astronomer and mathematician; designed what some claim to be the first ever self-propelled vehicle, which many claim this as the world's first automobile

Fr. Francesco de Vico (1805–1848) – Jesuit astronomer who discovered or co-discovered a number of comets; also made observations of Saturn and the gaps in its rings; the lunar crater De Vico and the asteroid 20103 de Vico are named after him

Fr. Vincent of Beauvais (c.1190–c.1264) – Dominican who wrote the most influential encyclopedia of the Middle Ages

Fr. Benito Viñes (1837–1893) – Jesuit meteorologist who made the first weather model to predict the trajectory of a hurricane

Archbishop János Vitéz (archbishop) (c.1405–1472) – Archbishop, astronomer and mathematician

Fr. Martin Waldseemüller (c. 1470–1520) – German priest and cartographer who, along with Matthias Ringmann, is credited with the first recorded usage of the word America

Fr. Godefroy Wendelin (1580–1667) – priest and astronomer who recognized that Kepler's third law applied to the satellites of Jupiter; the lunar crate Vendelinus is named in his honor

Fr. Johannes Werner (1468–1522) – priest, mathematician, astronomer and geographer

Fr. Witelo (c. 1230 – after 1280, before 1314) – Friar, physicist, natural philosopher and mathematician; lunar crater Vitello named in his honor; his Perspectiva powerfully influenced later scientists, in particular Johannes Kepler

Fr. Julian Tenison Woods (1832–1889) – Passionist geologist and mineralogist

Fr. Theodor Wulf (1868–1946) – Jesuit physicist who was one of the first experimenters to detect excess atmospheric radiation

Fr. Franz Xaver von Wulfen (1728–1805) – Jesuit botanist, mineralogist and alpinist

Fr. John Zahm (1851–1921) – Holy Cross priest and South American explorer

Fr. Giuseppe Zamboni (1776–1846) – priest and physicist who invented the Zamboni pile, an early electric battery similar to the Voltaic pile

Fr. Francesco Zantedeschi (1797–1873) – priest who was among the first to recognize the marked absorption by the atmosphere of red, yellow and green light; published papers on the production of electric currents in closed circuits by the approach and withdrawal of a magnet, thereby anticipating Michael Faraday's classical experiments of 1831

Fr. Niccolò Zucchi (1586–1670) – claimed to have tried to build a reflecting telescope in 1616 but abandoned the idea (maybe due to the poor quality of the mirror); may have been the first to see the belts on the planet Jupiter (1630)

Fr. Giovanni Battista Zupi (c. 1590–1650) – Jesuit astronomer, mathematician and first person to discover that the planet Mercury had orbital phases; the lunar crater Zupus is named after him.