Pi Gamma Mu or ΠΓΜ (from Πολιτικές Γνώσεως Μάθεται) is an international honor society in the social sciences.

Of greater concern among some of the leading scholars of the time was what they saw as the increasing tendency toward "sheer quantification" and "mensuration" in the traditional social science disciplines.

[1] The founders of the new honor society believed that "if the social sciences are to render any adequate service to humanity, factionalism, separatism, and dehumanization in them must be overcome.

[3] At a time when very few women held leadership positions anywhere, Pi Gamma Mu elected Grace Raymond Hebard, one of its founders, as national vice-president (1924–1931).

In 1955, the trustees of Pi Gamma Mu voted to grant a charter to the Pontifical Catholic University of Puerto Rico.

[7] In 1991 to enhance its international scope, the trustees approved the conferring of affiliate (or associate member) status on visiting fellows and exchange students who demonstrate academic excellence in their fields but are not otherwise expected to complete their degree programs at a Pi Gamma Mu sheltering college or university.

The unique influence of the Philippines Alpha chapter is recorded in Scott Johnston's work, Pi Gamma Mu International Honor Society in Social Science First 75 Years: “Again the quality of the people elected to the Philippines Alpha chapter has been most impressive.

The society's blue flag depicts a man and a woman jointly holding the torch of knowledge within the symbolic gold key and a wreath of Pi Gamma Mu.

An individual is traditionally invited or may petition to join an active collegiate chapter of Pi Gamma Mu when a junior, senior, or graduate student ranked in the upper 35 percent of their class, with at least twenty semester hours in social science courses with an average grade therein of "B" or better, and of good moral character.

A one-time induction fee covers these and the privilege of lifetime membership in Pi Gamma Mu, including participation in its various activities, attendance at scholarly meetings, and eligibility to compete for graduate fellowships.

Membership in Pi Gamma Mu can also advance a federal employee's civil service position grade or rating.

The Guest Lectureship Program of Pi Gamma Mu exists to advance social science interaction and serves as a memorial to deceased officers of the society.

Active chapters are eligible to apply for lectureship funds of $300.00 each year to cover the honoraria of guest lecturers.

The executive director of the society serves as an ex officio member of the governing board and oversees its day-to-day operations.

[10] In addition to former Pi Gamma Mu presidents Charles Abram Ellwood, S. Howard Patterson and W. Leon Godshall, prominent members of the society include former U.S. president Lyndon B. Johnson, 1956 Nobel Prize winner and former Canadian prime minister Lester B. Pearson, former Philippine presidents José P. Laurel and Ferdinand Marcos, Panama Canal Treaty negotiator and former Panama president Ricardo Joaquín Alfaro Jované, leading anthropologist Margaret Mead, sociologist Pitirim Sorokin (Pi Gamma Mu national vice-president, 1937–1941) who founded Harvard University's sociology department, Edward A. Ross, a major figure in early criminology, Ernst Philip Boas, famous cardiologist and inventor of the cardiotachometer and original proponent of national health insurance, Jane Addams, 1931 Nobel Prize winner and pioneer community worker, MIT economist Charles P. Kindleberger, architect of the Marshall Plan, incumbent US Senator Chuck Grassley of Iowa, incumbent Colorado Congresswoman Diana DeGette, deputy whip of the U.S. House of Representatives, groundbreaking experimental psychologist and incumbent Rockefeller Foundation president Judith Rodin - the first female president of an Ivy League university (University of Pennsylvania), incumbent commissioner of the Federal Communications Commission Michael Copps, incumbent Philippine Senators Edgardo Angara, Miriam Defensor Santiago and Juan Ponce Enrile, internationally recognized constitutionalist Henry J. Abraham, incumbent North Carolina Supreme Court senior justice Mark Martin, prominent California lawyer and former U.S. Attorney General William French Smith, banker, U.S. Secretary of the Treasury and Ambassador to NATO David M. Kennedy, 1971 Economics Nobel Prize winner Simon Kuznets, historian and 1949 Pulitzer Prize winner Roy Nichols, Paul Finkelstein, incumbent board chairman, president and chief executive officer of Regis Corporation, the worldwide leader in the hair salon industry and American football player Lem Burnham.

In 1928, Byrd carried the society's flag during a historic expedition to the Antarctic to dramatize the spirit of adventure into the unknown, characterizing both the natural and social sciences.