Many honor societies are referred to by their membership or by non-members as fraternities and sororities. Honor societies exist at the high school, collegiate/university, postgraduate, and professional levels, although university honor societies are by far the most prevalent. In the United States, the oldest academic society, Phi Beta Kappa, was founded as a social and literary fraternity in 1776. Other honor societies were established a century later, including Tau Beta Pi for engineering (1885), Sigma Xi for scientific research (1886), and Phi Kappa Phi for all disciplines (1897). Mortar Board was established in 1918 and was the first national honor society for women who were college seniors.
The origins of honor societies in the United States can be traced back to the establishment of Phi Beta Kappa in 1776 at the College of William and Mary, which began as a debating society and did not initially impose grade point average (GPA) restrictions for membership.
The Honor Society Caucus and Association of College Honor Societies (ACHS) are two voluntary associations for national collegiate and post-graduate honor societies. ACHS formed in 1925 to establish and maintain desirable standards for honor societies. Later, four prestigious founding members of ACHS established the Honor Society Caucus, expressing that the ACHS had diluted and lost sight of the mission of its founding members. While ACHS membership is a certification that the member societies meet these standards, not all legitimate honor societies apply for membership in ACHS.