An alumni association is an association of graduates (alumni) or, more broadly, of former students. In the United Kingdom and the United States, alumni of universities, colleges, schools (especially independent schools), fraternities, and sororities often form groups with alumni from the same organisation. These associations often organise social events, publish newsletters or magazines, and raise funds for the organisation. Many provide a variety of benefits and services that help alumni maintain connections to their educational institution and fellow graduates. In the US, most associations do not require its members to be an alumnus of a university to enjoy membership and privileges.

Additionally, such groups often support new alumni, and provide a forum to form new friendships and business relationships with people of similar background.

Alumni associations are mainly organised around universities or departments of universities, but may also be organised among students that studied in a certain country. In the past, they were often considered to be the university's or school's old boy society (or old boys network). Today, alumni associations involve graduates of all age groups and demographics.