ASEAN member countries
The eleven members of the Association of Southeast Asian Nations, in the order they joined: five founders in 1967, five more by 1999, and Timor-Leste, the newest, in 2025.
11 countriesAs of September 2026Short notes, not sourcedSuggest a correction
ASEAN was founded on 8 August 1967, when the foreign ministers of Indonesia, Malaysia, the Philippines, Singapore and Thailand signed the Bangkok Declaration. It was the height of the Vietnam War, and the five wanted to keep the peace among themselves and hold off communism in the region. Its secretariat is in Jakarta.
Today it covers every country in Southeast Asia, about 680 million people. It works by consultation and consensus, and its members have long agreed not to interfere in each other’s internal affairs, a habit known as the ASEAN Way. Critics say that makes it slow to act; supporters say it is why a region of such different governments has stayed together.
Founders (1967)5
The five countries that signed the Bangkok Declaration.
IndonesiaThe largest member by far, with about 40 percent of ASEAN’s people. The secretariat is in Jakarta.
MalaysiaIt had been in a low-level war with Indonesia, the Konfrontasi, until 1966, a year before they founded ASEAN together.
SingaporeHad become independent only two years before, when it left Malaysia in 1965.
ThailandThe declaration was signed in Bangkok. Thailand is the only member never colonised by a European power.
Joined later6
Brunei after its independence, then the countries of Indochina after the Cold War, and Timor-Leste in 2025.
BruneiJoined in January 1984, a week after it became fully independent from Britain.
VietnamJoined in 1995, twenty years after the war ended. It was ASEAN’s first communist member.
LaosJoined in 1997.
MyanmarJoined in 1997. Since the 2021 military coup, ASEAN has barred the junta’s leaders from its summits.
CambodiaIts entry was delayed by a coup in 1997, and it became the tenth member in 1999.
Timor-LesteBecame the eleventh member in October 2025, after applying in 2011. It had become independent in 2002, after 24 years of Indonesian occupation.
Close calls
Papua New Guinea
An observer since 1976. Its border with Indonesia runs across the island of New Guinea, but it is usually counted as part of Oceania, not Southeast Asia.
ASEAN Plus Three
China, Japan and South Korea meet ASEAN every year as ASEAN Plus Three, and many more countries, the United States and Russia among them, join the East Asia Summit. None of them is a member.
The South China Sea
Brunei, Malaysia, the Philippines and Vietnam all have claims in the South China Sea that overlap with China’s, while other members have close ties to Beijing. Because ASEAN decides by consensus, it has struggled to take a common line.
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