Founded in 1920, the International Association of Applied Psychology is the oldest and largest international association of individual members and affiliate international associations. Its official languages are English and French. As stated in Article 1 of its Constitution, its mission is:
...to promote the science and practice of applied psychology and to facilitate interaction and communication among applied psychologists around the world.
The Association distinguishes six membership categories: Full Members, Fellows, Student, Honorary, Affiliate Organizations and Alliance Members.