Association of Southeast Asian Nations

Regional · ASEAN

The adjective in the name is a wartime one, fixed in English by the Allied theatre command of 1943. British usage hyphenated it. The declaration signed at Bangkok on 8 August 1967 established an Association of South-East Asian Nations, and the Charter of 2007 spells the same words without the hyphen. Members have joined in ones and twos ever since, the most recent on 26 October 2025.

Questions about ASEAN

Which countries are in ASEAN?

Brunei, Cambodia, Indonesia, Laos, Malaysia, Myanmar, the Philippines, Singapore, Thailand, Timor-Leste and Vietnam. Five of them signed the founding declaration at Bangkok on 8 August 1967; the rest acceded between 1984 and 2025. The roster on this page is read from the association's own list of member states rather than assembled from country records, because a partial answer would be worse than none.

When did Timor-Leste join ASEAN?

On 26 October 2025, at a summit in Kuala Lumpur, by signing an instrument of accession to the Charter. The application had been lodged on 4 March 2011. The leaders agreed in principle to admit the country in 2022 and gave it observer status at meetings, a roadmap to full membership was adopted in 2023, and the admission took effect at the opening ceremony of the summit.

What does a country have to do to join ASEAN?

Article 6 of the Charter names four criteria: location in the recognised geographical region of Southeast Asia, recognition by all member states, agreement to be bound by the Charter, and the ability and willingness to carry out the obligations of membership. The summit decides by consensus, on the recommendation of the coordinating council, and the applicant signs an instrument of accession. Nothing in the Charter sets a deadline for a decision.

Is Papua New Guinea a member of ASEAN?

No. It was accorded special observer status in 1976 and has taken part in meetings in that capacity since, but it has not lodged an application for full membership and no accession instrument exists. Wikidata records it as a member, which is one reason the roster on this page is authored from the association's own list and dated.

Does ASEAN have a court?

No. Article 26 of the Charter refers an unresolved dispute to the summit for decision, and nothing above that. Members wanting a boundary settled in law have gone to the International Court of Justice by joint agreement: Indonesia and Malaysia over Ligitan and Sipadan, decided on 17 December 2002, and Malaysia and Singapore over Pedra Branca, decided on 23 May 2008.

What language does ASEAN work in?

English. Article 34 of the Charter is a single sentence saying so, and the Charter itself was done in a single original in that language. Each member keeps its own official languages, and the association publishes translations of the Charter in them, but the text that governs is the English one.

Sources

1967 ASEAN Declaration (Bangkok Declaration) · Centre for International Law, National University of Singapore. The naming clause, the seven aims, the machinery, the paragraph on foreign bases and the opening to all States in the region.
Charter of the Association of Southeast Asian Nations · ASEAN Secretariat. Articles 2, 3, 6, 11, 12, 20, 21, 26, 31, 34, 39 and 47, and the closing line recording Singapore, 20 November 2007, in a single original in English.
ASEAN Member States · ASEAN Secretariat. The roster used on this page and the accession dates of 1984, 1995, 1997, 1999 and 2025.
Forging a New Era: Timor-Leste Admitted into ASEAN · ASEAN Secretariat. The admission of 26 October 2025 at the summit in Kuala Lumpur.
ASEAN Leaders' Statement on the Application of Timor-Leste for ASEAN Membership · ASEAN Secretariat. The application of 4 March 2011, the agreement in principle of 2022 and observer status at meetings.
1976 Treaty of Amity and Cooperation in Southeast Asia · Centre for International Law, National University of Singapore. Adopted at Bali on 24 February 1976.
1976 Agreement on the Establishment of the ASEAN Secretariat · Centre for International Law, National University of Singapore. The same day at Bali, and the seat in Jakarta.
1995 Treaty on the Southeast Asia Nuclear Weapon-Free Zone · Centre for International Law, National University of Singapore. Article 1 defines the zone by naming the states in it and extends it to continental shelves and exclusive economic zones.
Treaty of Bangkok · United Nations Office for Disarmament Affairs. Signature on 15 December 1995, entry into force on 27 March 1997, and the unsigned protocol.
Sovereignty over Pulau Ligitan and Pulau Sipadan (Indonesia/Malaysia) · International Court of Justice. Brought by special agreement; judgment of 17 December 2002.
Sovereignty over Pedra Branca/Pulau Batu Puteh, Middle Rocks and South Ledge (Malaysia/Singapore) · International Court of Justice. Filed on 24 July 2003 by special agreement; judgment of 23 May 2008.
Southeast Asia: What's in a Name? · Donald K. Emmerson, Journal of Southeast Asian Studies 15(1), March 1984, pages 1 to 21. The wartime command, and the dropped hyphen.
Written Reply to Parliamentary Question on Papua New Guinea, 24 February 2023 · Ministry of Foreign Affairs, Singapore. Papua New Guinea accorded special observer status in 1976.