The Phi Beta Kappa Society is an academic honor society. Its mission is to "celebrate and advocate excellence in the liberal arts and sciences"; and induct "the most outstanding students of arts and sciences at America’s leading colleges and universities." Founded at The College of William and Mary on December 5, 1776, as the first collegiate Greek-letter fraternity, it is also the oldest honor society for the liberal arts and sciences and among the oldest undergraduate societies in the United States. Phi Beta Kappa (ΦΒΚ) stands for Φιλοσοφία Βίου Κυβερνήτης or philosophia biou kybernētēs — "Love of learning is the guide of life".

Each individual chapter determines its specific application of the Phi Beta Kappa Council's 1952 Stipulations Concerning Eligibility for Membership and sets its own academic standards.

Since inception, 17 U.S. Presidents, 37 U.S. Supreme Court Justices, 1 NFL MVP, 1 Heisman Trophy winner, and 136 Nobel Laureates have been inducted members.

According to the society, "only about 10 percent of the nation's institutions of higher learning have Phi Beta Kappa chapters," and of the institutions with chapters, only about 10 percent of the arts and sciences graduates are elected to Phi Beta Kappa membership.