The Association of Southeast Asian Nations (ASEAN , ) is a regional intergovernmental organisation comprising ten Southeast Asian states which promotes Pan-Asianism and intergovernmental cooperation and facilitates economic, political, military, educational and cultural integration amongst its members and Asian states. Since its formation on 8 August 1967 by Indonesia, Malaysia, the Philippines, Singapore, and Thailand, the organisation's membership has expanded to include Brunei, Cambodia, Laos, Myanmar, and Vietnam. Its principal aims include accelerating economic growth, social progress, and sociocultural evolution among its members, alongside the protection of regional stability and the provision of a mechanism for member countries to resolve differences peacefully. ASEAN is an official United Nations Observer. Communication by members across nations takes place in English. 

ASEAN covers a land area of 4.4 million square kilometres, 3% of the total land area of Earth. ASEAN territorial waters cover an area about three times larger than its land counterpart. Member countries have a combined population of approximately 625 million people, 8.8% of the world's population. In 2015, the organisation's combined nominal GDP had grown to more than US$2.8 trillion. If ASEAN were a single entity, it would rank as the sixth largest economy in the world, behind the USA, China, Japan, France and Germany. ASEAN shares land borders with India, China, Bangladesh, East Timor, and Papua New Guinea, and maritime borders with India, China, Palau, and Australia. Both East Timor and Papua New Guinea are backed by certain ASEAN members for their membership in the organisation.
What two countries do some members want to join?
East Timor and Papua New Guinea