Sigma Xi
ΣΞ
Founded	1886; 139 years ago (1886) Cornell University
Type	Honor Society
Affiliation	HSC
Former affiliation	ACHS
Status	Active
Emphasis	Science and Engineering
Scope	International
Motto	Companions in Zealous Research
Member badge
Colors	Blue and   Gold
Publication	American Scientist
Chapters	370 active, 170 inactive
Members	60,000[1] lifetime
Headquarters	3200 East NC Highway 54 Suite 300 Research Triangle Park, North Carolina 27709 United States
Website	www.sigmaxi.org

Sigma Xi, The Scientific Research Honor Society (ΣΞ) is an international non-profit honor society for scientists and engineers. Sigma Xi was founded at Cornell University by a junior faculty member and a small group of graduate students in 1886 and is one of the oldest honor societies.^[2][3] Membership in Sigma Xi is by invitation only, where members nominate others on the basis of their research achievements or potential.^[4] Sigma Xi goals aim to honor excellence in scientific investigation and encourage cooperation among researchers in all fields of science and engineering. Many of the world's most influential scientists have been members of Sigma Xi, such as Albert Einstein, Linus Pauling, Barbara McClintock, and Sally Ride.^[5][6]

Sigma Xi has nearly 60,000 members^[7] who were elected to membership based on their research achievements and potential. It has more than 500 chapters^[8] in North America and around the world. In addition to publishing American Scientist magazine, Sigma Xi provides grants^[9] annually to promising young researchers and sponsors a variety of programs supporting ethics in research, science and engineering education, the public understanding of science, international research cooperation and the overall health of the research enterprise. The Society is based in Research Triangle Park, North Carolina.

Sigma Xi was one of six honor societies that co-founded the Association of College Honor Societies (ACHS) on December 30, 1925.^[10] Its participation was short lived, with the decision to withdraw and operate again as an independent society made just over a decade later, effective in 1933.^[10] It resigned from ACHS because "it had decided to devote itself to research primarily, that it no longer considered itself a strictly college organization, and hence was somewhat outside of the field occupied by the Association, and that for these reasons it felt constrained to withdraw from the Association." ^[10]

Today, Sigma Xi participates in a more loosely coordinated lobbying association of four of the nation's oldest and most prestigious honor societies, called the Honor Society Caucus. Its members include Phi Beta Kappa, Phi Kappa Phi, Sigma Xi, and Omicron Delta Kappa.^[11]

Sigma Xi originated in 1886 at Cornell University. Founded by engineering students and Cornell faculty member, Frank Van Vleck, the society's primary objective was to acknowledge significant scientific research and foster cooperation among scientists from various disciplines.

By 1888, Sigma Xi included five female members and established chapters at educational institutions such as Rensselaer Polytechnic Institute, Union College, Stevens Institute of Technology, and Rutgers College. By the end of the 19th century, the society consisted of over 1,000 members in eight chapters.^[12]

In the early 20th century, following the 1906 San Francisco earthquake, Sigma Xi's Stanford and Berkeley chapters were involved in reconstruction and public health initiatives. The society later introduced the publication American Scientist, which discusses scientific and technological developments. During World War I, the National Research Council collaborated with Sigma Xi to organize research facilities. The society expanded significantly after the war, and by the 1930s, it had chapters at prestigious institutions like Harvard, Caltech, MIT, and Princeton.

Sigma Xi initiated the Distinguished Lectureships Program in the late 1930s, aimed at promoting its activities and research findings.^[13] By 1950, the society's membership numbered 42,000. In 1947, the Scientific Research Society of America (RESA) was created to support research in various settings. The two societies combined in 1974 under the name Sigma Xi, The Scientific Research Society. In 1989, Sigma Xi revised its mission statement, emphasizing the importance of science and its role in society. Currently, Sigma Xi has approximately 60,000 members in over 500 chapters worldwide. The society remains committed to recognizing scientific achievements and promoting global collaboration in science and technology. Notable past presidents of Sigma Xi include Frederick Robbins, a Nobel Prize recipient, and Rita Colwell, the former National Science Foundation Director.

The Greek letters "Sigma" and "Xi" form the acronym of the Society's motto, Σπουδῶν Ξυνῶνες or "Spoudon Xynones," which translates as "Companions in Zealous Research." The word 'Honor' was added to the name of the Society at the 2016 Annual Meeting.^[14] According to Sigma Xi President Tee L. Guidotti,

"Sigma Xi, of course, is our basic name and has been since the organization was founded in 1886 as the scientific and engineering counterpart to Phi Beta Kappa. Like all "Greek letter" societies, whether professional or social, it is an acronym for the motto of the organization, Σπουδων Ξυνωνες (Spoudon Xynones), which translates as "companions in Zealous Research." For many years, we were referred to as "Society of the Sigma Xi." In the early twentieth century, some in the leadership wanted "Sigma Xi" to be dropped altogether in favor of some formulation such as "Scientific Research Society of America." In a strange quirk of history, both names survived because the organization split in the 1940s into an academic honor society (Sigma Xi) and an honor society for applied research and engineering (the Scientific Research Society of America, called RESA). RESA was a separate entity, wholly owned by Sigma Xi, and represented engineers and scientists at non-academic institutions, such as government and industrial research laboratories. In an even stranger development, Sigma Xi and RESA merged back together in 1974 and eventually began calling itself Sigma Xi, The Scientific Research Society."^[14]

The William Procter Prize for Scientific Achievement is an award presented by Sigma Xi. This prestigious prize is given to a scientist who has made an outstanding contribution to scientific research and has demonstrated an ability to communicate the significance of this research to scientists in other disciplines.

The prize was established in 1950 in honor of William Procter, a distinguished business leader and philanthropist who had a strong commitment to scientific research and development.^[15] Procter was an heir to the Procter & Gamble Company and served as its president and chairman.

Recipients of the William Procter Prize are recognized for their achievements in both research and communication, reflecting the dual emphasis of Sigma Xi on promoting both scientific excellence and interdisciplinary communication.^[16] Along with the recognition, the awardee also delivers a lecture at the society's annual meeting or another appropriate occasion.

Over the years, the William Procter Prize has been awarded to many notable scientists from a wide range of disciplines, underscoring the prize's commitment to honoring and promoting interdisciplinary research.

As of May 4, 2023, 350 chapters are active in the United States, 170 are inactive, and the society has chartered over 20 chapters in other countries.

More than 200 winners of the Nobel Prize have been Sigma Xi members,^[17] including Albert Einstein, Enrico Fermi, Richard Feynman, Linus Pauling, Francis Crick, James Watson, Barbara McClintock, John Goodenough, and Jennifer Doudna.

• Alpha Chi Sigma, a professional fraternity specializing in the fields of the chemical sciences

• Official website
• Sigma Xi's Year of Water H2008 Blog
• Guide to the Sigma Xi, The Scientific Research Society Records 1928-2003