• Blake R. Van Leer – United States Army officer and president of Georgia Institute of Technology^[1]
• Eduardo Suger – Swiss-Guatemalan educator and founder of Galileo University^[2]
• Jeremy Howick – Canadian-British interdisciplinary researcher and founding director of the Stoneygate Centre for Excellence in Empathic Healthcare.^[3]
• Lois Lampe – American botanist and educator. Professor Emerita, The Ohio State University.^[4]
• Henry P. Rusk, dean of the department of agriculture, University of Illinois
• Fatima Cody Stanford – obesity medicine physician-scientist at Massachusetts General Hospital and Associate Professor of Medicine and Pediatrics at Harvard Medical School^[5]

• Ali Baghchehsara – Vice President of Solar Maximum Co. and coauthor of Electric Space: Space-Based Solar Power Technologies & Applications^[6][7]
• Irmgard Flügge-Lotz  – developed the theory of discontinuous automatic control; first female engineering professor at Stanford University and first female engineer elected a Fellow of the American Institute of Aeronautics and Astronautics.
• Jack Parsons - American rocket engineer, rocket propulsion researcher, chemist, and a leading member of the OTO occult group.

• Eugenie Scott – leading critic of young earth creationism and intelligent design^[8]

Botany edit

• Don G. Despain – flora of Yellowstone National Park specialist^[9]
• Edwin Earle Honey (1891–1956) – American plant pathologist and mycologist^[10]
• Barbara McClintock – cytogenetics specialist, Nobel Prize in Physiology or Medicine winner^[11]
• Peter H. Raven – President Emeritus of the Missouri Botanical Garden^[12]
• Julia Warner Snow – American systematic phycologist and instructor.^[13]

Entomology edit

• Anna Botsford Comstock – insect illustrator, leader in the nature study movement, and one of the first four female members of Sigma Xi
• Marion Durbin Ellis – ichthyologist and entomologist^[14]

Molecular biology edit

• Francis Crick – co-discoverer of the structure of the DNA molecule, Nobel Prize in Physiology or Medicine winner
• Jennifer Doudna - pioneer in CRISPR gene editing, Nobel Prize in Chemistry winner^[15]
• James D. Watson – co-discoverer of the structure of DNA, Nobel Prize in Physiology or Medicine winner

Zoology edit

• Roger Arliner Young – first African American woman to receive a PhD in zoology^[16]
• William Rees Brebner Robertson - American zoologist and early cytogeneticist who discovered the chromosomal rearrangement named in his honour, Robertsonian translocation^[17]
• Florence Wells Slater - American entomologist^[18]

• Arthur W. Adamson – inorganic photochemistry pioneer^[19]
• Arthur A. Noyes - Chemist and inventor^[20]
• Bettye Washington Greene  – Dow Chemical^[21]
• Narayan Sadashiv Hosmane – Humboldt Prize winner^[22]
• Ray R. Irani – current chairman and former chief executive officer of Occidental Petroleum^[23]
• Irving Langmuir – research helped develop the incandescent light bulb, Nobel Prize in Chemistry winner^[24][25]
• Tobin J. Marks – National Medal of Science laureate^[23]
• Donna Nelson – President of Oklahoma Sigma Xi Chapter, American Chemical Society (ACS) President (2016), Breaking Bad science advisor (2008-2013).
• Linus Pauling – Nobel Prize in Chemistry winner^[26]
• Harry Snyder – President of Minnesota Sigma Xi Chapter^[27]
• Kelly O. Sullivan – Sigma Xi President, 2012-2013
• Theodor Svedberg – Nobel Prize in Chemistry winner^[24]
• Harold Urey – discovery of deuterium, Nobel Prize in Chemistry winner^[28]
• Khairat Muhammad Ibne Rasa - Winner of the Potter Prize, Brown University 1959

• Alan Sherman – Cryptologia editor
• Michael Waterman – computational biology specialist^[23]

Chemical engineering edit

• Frances Arnold - Nobel Prize in Chemistry winner for directed evolution

Electrical engineering edit

• Supriyo Datta – Director of NASA Institute for Nanoelectronics and Computing^[23]
• Alan V. Oppenheim – Developed the field of digital signal processing and member of the National Academy of Engineering

Mechanical engineering edit

• Catherine Mohr  – surgical roboticist and faculty of Stanford School of Medicine

• Katherine T. Faber - world expert in ceramics and originator of the Faber-Evans model for crack deflection
• John B. Goodenough - developer of the lithium-ion battery and winner of the Nobel Prize in Chemistry
• Galen D. Stucky - expert in mesoporous materials

• Albert Turner Bharucha-Reid – probability and Markov chain theorist
• James McMahon – delegate to First Convention of Sigma Xi^[29]
• John von Neumann – Enrico Fermi Award winner^[11]
• Cornelia Strong – professor of mathematics and astronomy

• John C. Cook – played a crucial role in establishing the field of ground-penetrating radar^[30]
• Richard J. Duffin – mathematical physicist noted for contributions to electrical transmission theory and geometric programming
• Albert Einstein – developed the general theory of relativity, Nobel Prize in Physics winner
• Richard Feynman – Nobel Prize in Physics winner^[11]
• Enrico Fermi – Chicago Pile team member, Nobel Prize in Physics winner
• Andrea Ghez - astrophysicist, Nobel Prize in Physics winner^[15]
• Mustapha Ishak Boushaki – gravitational lensing and universe expansion physicist, University of Texas at Dallas
• Ernest Merritt – Dean of the Graduate School, Cornell University
• Robert A. Millikan - Nobel Prize in Physics winner, president of Caltech^[31]
• Rahul Pandit – condensed matter physicist, Shanti Swarup Bhatnagar laureate
• Andrea Prosperetti – multiphase flow researcher^[23]

• Marie Skodak Crissey – developmental psychologist, served as president of two divisions of the American Psychological Association

• Natalie Angier – journalist^[32]
• Deborah Blum – Pulitzer Prize-winning journalist^[32]
• Sherwood Boehlert – member of the United States House of Representatives^[32]
• George Brown, Jr. – member of the United States House of Representatives^[32]
• Malcolm Browne – photojournalist^[32]
• Clinton Sumner Burns  – civil engineer ^[33]
• William D. Carey – publisher of Science^[32]
• Barbara Culliton – science journalist and editor
• Claudia Dreifus – journalist^[32]
• Dennis Flanagan – founding editor of Scientific American^[32]
• Ira Flatow – Science Friday host^[32]
• Al Gore – Vice President of the United States, Nobel Peace Prize winner^[32]
• Sidney Harris – cartoonist^[32]
• Brian Hayes – science writer^[32]
• Theodore Hesburgh – President Emeritus of the University of Notre Dame^[32]
• Jamie Hyneman – MythBusters co-host^[32]
• Bill Kurtis – television journalist^[32]
• Bob McDonald – journalist^[32]
• Dennis Overbye – science writer^[32]
• David Price – member of the United States House of Representatives^[32]
• David Quammen – science writer^[32]
• Paul Raeburn – science writer^[32]
• Floyd M. Riddick – Parliamentarian of the United States Senate^[32]
• Adam Savage – MythBusters co-host^[32]
• David Sington – BBC journalist^[32]
• Walter S. Sullivan – New York Times journalist^[32]
• Robert Dillard Teer Jr. – Real Estate Developer and General Contractor^[32]
• Stewart Udall – Secretary of the Interior during John F. Kennedy and Lyndon B. Johnson administrations^[32]

• Sigma Xi's "Members in the News"