In this biography
Quick facts
- Born
- 9 May 1914
- Died
- 3 March 2016
- Birthplace
- Bangkok, Siam
- Country
- Thailand
- Nationality
- Thai
- Known for
- Helping create ASEAN and signing the Bangkok Declaration in 1967
- Foreign minister
- 10 February 1959 – 17 November 1971
- Earlier regional body
- Association of Southeast Asia, 1961
- Founding document
- ASEAN Declaration, 8 August 1967
- Later office
- Deputy prime minister, 1980–1983
Why this life matters
Thanat connected Thailand’s professional diplomacy to a distinctly Southeast Asian regional project, first through ASA and then through the negotiations that established ASEAN.
Timeline
Key moments
Born in Bangkok
Born in Siam’s capital on 9 May.
Joined the foreign ministry
Entered Thailand’s diplomatic service after completing legal and international studies in France.
Became foreign minister
Began a twelve-year tenure that placed regional diplomacy at the centre of Thai foreign policy.
Helped establish ASA
Thailand, Malaya and the Philippines formed the Association of Southeast Asia, an important precursor to ASEAN.
Signed the Bangkok Declaration
Joined Adam Malik, Tun Abdul Razak, Narciso Ramos and S. Rajaratnam in founding ASEAN on 8 August.
Became deputy prime minister
Returned to cabinet office under Prime Minister Prem Tinsulanonda after leading the Democrat Party.
Died at age 101
Died in Bangkok as the last surviving signatory of the 1967 ASEAN Declaration.
A professional diplomat in a divided region
Thanat studied law and international affairs in Bordeaux and Paris before entering the Royal Thai Ministry of Foreign Affairs in 1940. Assignments in Tokyo, Washington, New Delhi and at the United Nations gave him experience across wartime, decolonisation and the early Cold War.
As foreign minister from 1959 to 1971, he treated cooperation among Southeast Asian governments as a practical answer to insecurity and diplomatic isolation. The Association of Southeast Asia, created by Malaya, the Philippines and Thailand in 1961, was limited and soon disrupted by regional disputes, but it supplied both experience and an unfinished institutional idea.
From reconciliation to the Bangkok Declaration
After Indonesia–Malaysia Confrontation ended, Thailand helped broker reconciliation among Indonesia, Malaysia and the Philippines. Thanat later recalled proposing a broader regional organisation to Indonesian foreign minister Adam Malik while the Thai foreign ministry prepared a working draft.
The five ministers negotiated informally at Bang Saen and returned to Bangkok to sign the ASEAN Declaration on 8 August 1967. Its compact articles tied cooperation in development, education and culture to peace, stability, law and openness to other Southeast Asian states.
A regional legacy beyond ministerial office
Thanat continued advising Thai governments on foreign affairs after leaving the ministry. He later led the Democrat Party and served as deputy prime minister under Prem Tinsulanonda, while remaining closely associated with the institution he had helped create.
ASEAN formally honoured the five Bangkok Declaration signatories in 1997. By Thanat’s death in 2016, the association had expanded from five members to ten and had inaugurated the ASEAN Community, giving his early argument for an inclusive regional framework a durable institutional legacy.
Quick answers
Frequently asked questions about Thanat Khoman
- Who was Thanat Khoman?
- Thanat Khoman was a diplomat, foreign minister and ASEAN co-founder. Thanat connected Thailand’s professional diplomacy to a distinctly Southeast Asian regional project, first through ASA and then through the negotiations that established ASEAN.
- What is Thanat Khoman best known for?
- Thanat Khoman is best known for helping create ASEAN and signing the Bangkok Declaration in 1967.
- When and where was Thanat Khoman born?
- Thanat Khoman was born on 9 May 1914 in Bangkok, Siam.
- When did Thanat Khoman die?
- Thanat Khoman died on 3 March 2016.
Sources and further reading
How this biography was checked
Core dates and offices are checked against the sources below. This profile was last reviewed on 9 September 2026.
