The International Federation of Vexillological Associations (FIAV, French acronym: Fédération internationale des associations vexillologiques) is an international federation of 55 regional, national, and multinational associations and institutions across the globe that study vexillology, which FIAV defines in its constitution as "the creation and development of a body of knowledge about flags of all types, their forms and functions, and of scientific theories and principles based on that knowledge."