The Association of Southeast Asian Nations (ASEAN  /ˈɑːsi.ɑːn/ AH-see-ahn, rarely /ˈɑːzi.ɑːn/ AH-zee-ahn) is a geo-political and economic organization of ten countries located in Southeast Asia, which was formed on 8 August 1967 by Indonesia, Malaysia, the Philippines, Singapore and Thailand. Since then, membership has expanded to include Brunei, Burma (Myanmar), Cambodia, Laos, and Vietnam. Its aims include accelerating economic growth, social progress, cultural development among its members, protection of regional peace and stability, and opportunities for member countries to discuss differences peacefully.

ASEAN covers a land area of 4.46 million km², which is 3% of the total land area of Earth, and has a population of approximately 600 million people, which is 8.8% of the world's population. The sea area of ASEAN is about three times larger than its land counterpart. In 2010, its combined nominal GDP had grown to US$1.8 trillion. If ASEAN were a single entity, it would rank as the ninth largest economy in the world, behind the United States, China, Japan, Germany, France, Brazil, the United Kingdom, and Italy.