College of William & Mary fraternity and sorority system

Alpha Epsilon Pi (ΑΕΠ), commonly known as AEPi, is a college fraternity founded at New York University in 1913 by Charles C. Moskowitz and ten other men. The fraternity has more than 150 active chapters across the United States, Canada, United Kingdom, and Israel, and has initiated more than 110,000 members. Although the fraternity is based upon Jewish principles, it is non-discriminatory and is open to all who are willing to espouse its purpose and values.

Alpha Sigma Phi (ΑΣΦ), commonly known as Alpha Sig, is an intercollegiate men's social fraternity with 181 active chapters and provisional chapters. Founded at Yale in 1845, it is the 10th oldest Greek letter fraternity in the United States.

Alpha Tau Omega (ΑΤΩ), commonly known as ATO, is an American social fraternity founded at the Virginia Military Institute in 1865 by Otis Allan Glazebrook. The fraternity has around 250 active and inactive chapters and colonies in the United States and has initiated more than 229,000 members. VMI Cadets are no longer associated with the fraternity. In 1885, the VMI Board of Visitors ruled that cadets could no longer join fraternities based on the belief that allegiance to a fraternal group undermined the cohesiveness of and loyalty to the Corps of Cadets.

Beta Theta Pi (ΒΘΠ), commonly known as Beta, is a North American social fraternity that was founded in 1839 at Miami University in Oxford, Ohio. One of North America's oldest fraternities, as of 2022 it consists of 144 active chapters in the United States and Canada. More than 219,000 members have been initiated worldwide and there are currently around 8,500 undergraduate members. Beta Theta Pi is the oldest of the three fraternities that formed the Miami Triad, along with Phi Delta Theta and Sigma Chi.

Delta Chi (ΔΧ) is an international Greek letter collegiate social fraternity formed on October 13, 1890, at Cornell University, initially as a professional fraternity for law students. On April 30, 1922, Delta Chi became a general membership social fraternity, eliminating the requirement for men to be studying law, and opening membership to all areas of study. Delta Chi became one of the first international fraternities to abolish "hell week", when it did so on April 22, 1929. Delta Chi is a charter member of the North American Interfraternity Conference (NIC). As of Fall 2019, Delta Chi has initiated over 116,000 members at over 110 Chapters and Colonies, with 34 Alumni Chapters. Its headquarters is in Indianapolis, Indiana.

Kappa Alpha Order (ΚΑ), commonly known as Kappa Alpha or simply KA, is a social fraternity and a fraternal order founded in 1865 at Washington and Lee University in Lexington, Virginia. As of December 2015, the Kappa Alpha Order lists 133 active chapters, five provisional chapters, and 52 suspended chapters. Along with Alpha Tau Omega and Sigma Nu, the order constitutes the Lexington Triad. Since its establishment in 1865, the Order has initiated more than 150,000 members.

Kappa Delta Rho (ΚΔΡ), commonly known as KDR, is an American college social fraternity, with 84 chapters spread out over the United States, primarily in the Midwest and Mid-Atlantic regions. Kappa Delta Rho's open motto is "Honor Super Omnia", or "Honor Above All Things".

Kappa Sigma (ΚΣ), commonly known as Kappa Sig, is an American collegiate social fraternity founded at the University of Virginia in 1869. Kappa Sigma is one of the five largest international fraternities with currently 318 active chapters and colonies in North America. Its endowment fund, founded in 1919, has donated more than $5 million to undergrads since 1948. In 2012 alone, the Fraternity's endowment fund raised over $1 million in donations.

Lambda Chi Alpha (ΛΧΑ), commonly known as Lambda Chi, is a college fraternity in North America. It was founded at Boston University in 1909. Lambda Chi Alpha is one of the largest social fraternities in North America with over 300,000 lifetime members and active chapters and colonies at 195 universities.

Phi Gamma Delta (ΦΓΔ), commonly known as Fiji, is a social fraternity with more than 144 active chapters and 10 colonies across the United States and Canada. It was founded at Jefferson College, Pennsylvania, in 1848. Along with Phi Kappa Psi, Phi Gamma Delta forms a half of the Jefferson Duo. Since its founding in 1848, the fraternity has initiated more than 196,000 brothers. The nickname FIJI is used commonly by the fraternity due to Phi Gamma Delta bylaws that limit the use of the Greek letters.

Psi Upsilon (ΨΥ), commonly known as Psi U, is a North American fraternity, founded at Union College on November 24, 1833. The fraternity reports 50 chapters at colleges and universities throughout North America, some of which are inactive.

Sigma Alpha Epsilon (ΣΑΕ), commonly known as SAE, is a North American Greek-letter social college fraternity. It was founded at the University of Alabama in Tuscaloosa, Alabama, on March 9, 1856. Of all existing national social fraternities today, Sigma Alpha Epsilon is the only one founded in the Antebellum South. Its national headquarters, the Levere Memorial Temple, was established on the campus of Northwestern University in Evanston, Illinois, in 1929. The fraternity's mission statement is "To promote the highest standards of friendship, scholarship and service for our members throughout life."

Delta Phi (ΔΦ) is a fraternity founded in 1827 at Union College in Schenectady, New York consisting of ten active chapters along the East Coast of the United States. The fraternity also uses the names "St. Elmo," "St. Elmo Hall," or merely "Elmo" because of its relation to Erasmus of Formia with some chapters known almost exclusively by one of these names on their respective campuses. Delta Phi was, after the Kappa Alpha Society and Sigma Phi Society, the third and last member of the Union Triad.

Pi Kappa Alpha (ΠΚΑ), commonly known as PIKE, is a college fraternity founded at the University of Virginia in 1868. The fraternity has over 225 chapters and colonies across the United States and abroad with over 15,500 undergraduate members and over 300,000 lifetime initiates.

Phi Kappa Tau (ΦΚΤ), commonly known as Phi Tau, is a collegiate fraternity located in the United States. The fraternity was founded in 1906. As of March 2023, the fraternity has 161 chartered chapters, 82 active chapters, 7 Associate chapters and about 3,500 collegiate members. SeriousFun Children's Network, founded by Beta chapter alumnus Paul Newman, is Phi Kappa Tau's National Philanthropy. According to its Constitution, Phi Kappa Tau is one of the few social fraternities that can accept graduate students as well as undergraduates.

Chi Phi (ΧΦ) is considered by some as the oldest American men's college social fraternity that was established as the result of the merger of three separate organizations that were each known as Chi Phi. The earliest of these organizations was formed at Princeton University in 1824. Today, Chi Phi has over 47,000 living alumni members from over 100 active and inactive chapters and un-chartered associate chapters. Currently Chi Phi has about 48 active chapters.

Theta Delta Chi (ΘΔΧ) is a social fraternity that was founded in 1847 at Union College, New York, United States. While nicknames differ from institution to institution, the most common nicknames for the fraternity are TDX, Thete, Theta Delt, and Thumpers. Theta Delta Chi brothers refer to their local organization as charges rather than using the common fraternity nomenclature of chapters.

Sigma Nu (ΣΝ) is an undergraduate college fraternity founded at the Virginia Military Institute on January 1, 1869. The fraternity was founded by James Frank Hopkins, Greenfield Quarles and James McIlvaine Riley shortly after Hopkins witnessed what he considered a hazing ritual by upperclassmen at the Virginia Military Institute. The fraternity's existence remained secret until the founders publicly announced their new society on January 1, 1869. Since its founding, Sigma Nu has amassed more than 279 active and inactive chapters and colonies across the United States and Canada and has initiated more than 227,000 members. Sigma Nu, Kappa Alpha Order and Alpha Tau Omega make up the Lexington Triad.

Pi Lambda Phi (ΠΛΦ), commonly known as Pi Lam, is a social fraternity with 145 chapters. The fraternity was founded in 1895 at Yale University in New Haven, Connecticut. Pi Lambda Phi is headlined by prestigious chapters at Temple University, the Massachusetts Institute of Technology, and the University of Virginia. Pi Lambda Phi is continuously expanding to schools across the country, such as Ohio State University, University of Cincinnati, Pennsylvania State University, Florida State University and East Carolina University. Recent planned expansions include West Virginia University and the University of Pennsylvania.

Alpha Chi Omega is a national women's fraternity founded on October 15, 1885.

Chi Omega is a women's fraternity and a member of the National Panhellenic Conference, the umbrella organization of 26 women's fraternities.

Delta Delta Delta (ΔΔΔ), also known as Tri Delta, is an international women's fraternity founded on November 27, 1888 at Boston University by Sarah Ida Shaw, Eleanor Dorcas Pond, Isabel Morgan Breed, and Florence Isabelle Stewart.

Delta Gamma (ΔΓ), commonly known as DG, is a women's fraternity in the United States and Canada with over 250,000 initiated members. It has 150 collegiate chapters and more than 200 alumnae groups. The organization's executive office is in Columbus, Ohio. Delta Gamma is one of 26 national fraternities under the umbrella organization of the National Panhellenic Conference.

Gamma Phi Beta is an international college sorority. It was founded in Syracuse University in 1874, and was the first of the Greek organizations to call itself a sorority. The term "sorority" was coined for Gamma Phi Beta by Dr. Frank Smalley, a professor at Syracuse University.

Kappa Alpha Theta (ΚΑΘ), also known simply as Theta, is an international women’s fraternity founded on January 27, 1870, at DePauw University, formerly Indiana Asbury. It was the first Greek-letter fraternity established for women. The fraternity was founded by four female students, Bettie Locke Hamilton, Alice Allen Brant, Bettie Tipton Lindsey, and Hannah Fitch Shaw. The organization has 147 chapters at colleges and universities in the United States and Canada. The organization was the first women's fraternity to establish a chapter in Canada. Theta's total living initiated membership, as of 2020, was more than 250,000. There are more than 200 alumnae chapters and circles worldwide.

Kappa Delta was the first sorority founded at the State Female Normal School, in Farmville, Virginia.

Kappa Kappa Gamma (ΚΚΓ), also known simply as Kappa or KKG, is a collegiate sorority founded at Monmouth College in Monmouth, Illinois, United States.

Phi Mu (ΦΜ) is the second oldest female fraternal organization established in the United States.

Pi Beta Phi (ΠΒΦ), often known simply as Pi Phi, is an international women's fraternity founded at Monmouth College, in Monmouth, Illinois on April 28, 1867 as I. C. Sorosis, the first national secret college society of women to be modeled after the men's Greek-letter fraternity.

Alpha Phi Alpha Fraternity, Inc. (ΑΦΑ) is the oldest intercollegiate historically African American fraternity. It was initially a literary and social studies club organized in the 1905–1906 school year at Cornell University but later evolved into a fraternity with a founding date of December 4, 1906. It employs an icon from Ancient Egypt, the Great Sphinx of Giza, as its symbol. Its aims are "Manly Deeds, Scholarship, and Love For All Mankind," and its motto is "First of All, Servants of All, We Shall Transcend All." Its archives are preserved at the Moorland-Spingarn Research Center.

Alpha Kappa Alpha Sorority, Inc. (ΑΚΑ) is the first intercollegiate historically African American sorority. The sorority was founded on January 15, 1908, at the historically black Howard University in Washington, D.C., by a group of sixteen students led by Ethel Hedgemon Lyle. Forming a sorority broke barriers for African American women in areas where they had little power or authority due to a lack of opportunities for minorities and women in the early 20th century. Alpha Kappa Alpha was incorporated on January 29, 1913.

Delta Sigma Theta Sorority, Inc. (ΔΣΘ) is a historically African American sorority. The organization was founded by college-educated women dedicated to public service with an emphasis on programs that assist the African American community. Delta Sigma Theta was founded on January 13, 1913, by twenty-two women at Howard University in Washington, D.C. Membership is open to any woman who meets the requirements, regardless of religion, race, or nationality. Women may apply to join through undergraduate chapters at a college or university or through an alumnae chapter after earning a college degree.

Kappa Alpha Psi Fraternity, Inc. (ΚΑΨ) is a historically African American fraternity. Since the fraternity's founding on January 5, 1911 at Indiana University Bloomington, the fraternity has never restricted membership on the basis of color, creed or national origin though membership traditionally is dominated by those of African heritage. The fraternity has over 160,000 members with 721 undergraduate and alumni chapters in every state of the United States, and international chapters in the United Kingdom, Germany, South Korea, Japan, United States Virgin Islands, Nigeria, South Africa, and The Bahamas.

Phi Beta Sigma Fraternity, Inc. (ΦΒΣ) is a historically African American fraternity. It was founded at Howard University in Washington, D.C. on January 9, 1914, by three young African-American male students with nine other Howard students as charter members. The fraternity's founders, A. Langston Taylor, Leonard F. Morse, and Charles I. Brown, wanted to organize a Greek letter fraternity that would exemplify the ideals of Brotherhood, Scholarship and Service while taking an inclusive perspective to serve the community as opposed to having an exclusive purpose. The fraternity exceeded the prevailing models of Black Greek-Letter fraternal organizations by being the first to establish alumni chapters, youth mentoring clubs, a federal credit union, chapters in Africa and a collegiate chapter outside of the United States. It is the only fraternity to hold a constitutional bond with a historically African-American sorority, Zeta Phi Beta (ΖΦΒ), which was founded on January 16, 1920 at Howard University in Washington, D.C., through the efforts of members of Phi Beta Sigma.

Sigma Gamma Rho Sorority, Inc. (ΣΓΡ) is a historically African American sorority, international collegiate, and non-profit community service organization that was founded on November 12, 1922, by seven educators on the Irvington campus (1875–1928) of Butler University in Indianapolis, Indiana. At its inception, the sorority was created to support Black women pursing degrees in education, and later in other disciplines. It was incorporated within Indiana in November 1922 and quickly grew, holding their first national conference in 1925. The sorority became a national collegiate sorority on December 30, 1929, when a charter was granted to the Alpha chapter. Sigma Gamma Rho is the only sorority of the four historically African American National Pan-Hellenic Council sororities established at a predominantly white institution instead of at Howard University. The sorority's slogan is "Greater Service, Greater Progress".

Zeta Phi Beta Sorority, Inc. (ΖΦΒ) is a historically African American sorority. In 1920, five women from Howard University envisioned a sorority that would raise the consciousness of their people, encourage the highest standards of scholastic achievement, and foster a greater sense of unity among its members. These women believed that sorority elitism and socializing overshadowed the real mission for progressive organizations. Since its founding Zeta Phi Beta has historically focused on addressing social causes.

Omega Psi Phi Fraternity, Inc. (ΩΨΦ) is a historically African-American fraternity. The fraternity was founded on November 17, 1911, the first at a historically black university, by three Howard University students, Edgar Amos Love, Oscar James Cooper and Frank Coleman, and their faculty adviser, Dr. Ernest Everett Just. Since its founding the organization has chartered over 750 undergraduate and graduate chapters.

Alpha Kappa Psi is the oldest and largest business fraternity to current date. Also known as "AKPsi", the fraternity was founded on October 5, 1904, at New York University and was incorporated on May 20, 1905. It is currently headquartered in Noblesville, Indiana.

Alpha Lambda Delta (ΑΛΔ) is an honor society for students who have achieved a 3.5 GPA or higher during their first year or term of higher education.

Alpha Phi Omega (ΑΦΩ), commonly known as APO, but also A-Phi-O and A-Phi-Q, is a coeducational service fraternity. It is the largest collegiate fraternity in the United States, with chapters at over 350 campuses, an active membership of over 25,000 students, and over 500,000 alumni members. There are also 250 chapters in the Philippines, one in Australia and one in Canada. The 500,000th member was initiated in the Rho Pi chapter of Alpha Phi Omega at the University of California, San Diego.

Beta Gamma Sigma (ΒΓΣ) is the International Business Honor Society. Founded in 1913 at the University of Wisconsin, University of Illinois and the University of California, it has over 980,000 members, selected from more than 600 collegiate chapters in business schools accredited by AACSB International. Founded in the United States, it has collegiate chapters in over 190 countries.

Delta Omicron (ΔΟ) is a co-ed international professional music honors fraternity whose mission is to promote and support excellence in music and musicianship.

Eta Sigma Phi (ΗΣΦ) is a collegiate honor society for the study of Classics. It grew out of a local undergraduate classical club founded by a group of students in the Department of Greek at the University of Chicago in 1914. This organization later united with a similar organization at Northwestern University and became Phi Sigma. Phi Sigma became a national fraternity in 1924, organizing chapters at leading colleges and universities.

Kappa Delta Pi International Honor Society in Education, (ΚΔΠ) is an honor society for education. It was founded in 1911 and was one of the first discipline-specific honor societies. Its membership is limited to the top 20 percent of those entering the field of education.

Phi Alpha Delta Law Fraternity, International is the largest professional law fraternity in the United States. Founded in 1902, P.A.D. has since grown to 717 established pre-law, law, and alumni chapters and over 330,000 initiated members. Application for membership to Phi Alpha Delta is available to undergraduate students, law school students, lawyers, judges, and politicians.

Phi Alpha Theta (ΦΑΘ) is an American honor society for undergraduate and graduate students and professors of history. It has more than 400,000 members, with new members numbering about 9,000 a year through its 970 chapters.

The Phi Beta Delta Society (ΦΒΔ) is an international honor society that was founded at California State University, Long Beach on February 27, 1986. It was the first honor society dedicated to recognize scholarly achievement in international involvement and education, to give scholarships to deserving students and to enhance knowledge about various cultures around the world. It was established as a national organization in 1987 with 38 chartered chapters, and has grown to become an international organization with over 179 chapters.