Phillips Academy has had a long tradition of secret societies. Almost from the inception of the school, societies existed publicly, with buildings that the students could use as clubhouses. While the societies held secret initiation rituals, their presence was recognized as part of academy life. In the 1940s their existence was widely criticized, even drawing the attention of then Secretary of War Henry Stimson, an Andover and society alum. Objections included racist exclusion, vicious hazing, and the poor academic performance of society members. Bending to public pressure, societies were disbanded in 1949 by Headmaster Kemper.

Although all secret societies were officially terminated in the 1940s, some societies still exist to this day (citation needed). During the academic year's extended period weeks (weeks during which term examinations take place), a bath tub filled with canned drinks appears on the terrace of the Oliver Wendell Holmes Library. An all-boys society called TUB (Truth, Unity, Brotherhood) is responsible for this action.A female counterpart, MSAS (Madame Sarah Abbot Society), also remains active.