Coup Atlas Research Database
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80009161957SuccessfulMilitary coup

Thailand, 1957 — military coup

Thailand (THA)Southeast Asia, AsiaSeptember 16, 1957

Event Summary

On September 16-17, 1957, the commander-in-chief of the Thai army, Field Marshal Sarit Thanarat, led a bloodless coup that overthrew the decade-long government of Prime Minister Plaek Phibunsongkhram (Phibun) and drove both Phibun and the powerful police chief Phao Siyanon into exile. The crisis grew out of the blatantly rigged February 1957 election, which sparked public outrage and student protests, and out of the three-way power struggle among Phibun, Phao, and Sarit. Distancing himself from the corrupt ruling party, Sarit publicly called the election the dirtiest ever and, on September 13, delivered an ultimatum signed by 58 officers demanding Phibun's resignation.

After mass demonstrations and with the tacit approval of King Bhumibol, Sarit's troops seized Bangkok in the early morning. Phibun fled the country and Phao was deported. The coup marked a turning point that entrenched military dominance and revived the public role of the monarchy in Thai politics.

Researched Details

Researched

Independent research, added record by record. Hover any label for what it means.

Target identified in Coup Atlas research: Plaek Phibunsongkhram (Phibun), Prime Minister of Thailand (overthrown, fled the country)
RESEARCHED NAME
Key figures
Plaek Phibunsongkhram (deposed prime minister)
Sarit Thanarat (army commander and coup leader)
Phao Siyanon (police chief, deported)
King Bhumibol Adulyadej (whose approval aided the coup)

Sources

On 16 September 1957 Thailand experienced a bloodless military coup led by Field Marshal Sarit Thanarat that ended the government of Prime Minister Phibunsongkhram, whose administration had faced criticism for corruption and the fraudulent February 1957 election.
SOURCE REVIEWED Wikipedia, "1957 Thai coup d'etat" open source ↗
Under Sarit's leadership the army quickly took control of key locations in Bangkok, forcing Phibun and Phao to flee the country; the king soon declared martial law and recognized the new rulers.
SOURCE REVIEWED Wikipedia, "1957 Thai coup d'etat" open source ↗
On 13 September 1957 Sarit handed Phibun an ultimatum signed by 58 army officers calling for the government's resignation; after mass demonstrations, Sarit and his army staged the coup the following morning.
SOURCE REVIEWED Wikipedia, "Sarit Thanarat" open source ↗
In the early morning of 17 September 1957 army commander Sarit Thanarat used military force to seize power, removing the increasingly corrupt Phibun; the elections of March 1957 were considered dirty even by Thai standards.
SOURCE REVIEWED EBSCO Research Starters, "Thai Military Coup" open source ↗

Editorial Note

Sources date the coup to the night of 16-17 September 1957 (the Cline dataset codes 16 September) and agree Phibun fled the country, matching the dataset's leader fate. Three Wikipedia-derived sources and EBSCO were read directly. This coup ended Phibun's long career (he had returned to power in the 1947 coup, another record in this dataset) and began the Sarit era.

Cross-Reference

Datasets agree. At least two of the three reference datasets we check against carry this event, and none of them disagrees about its date or its result.

Identifiers for finding this same event in the other datasets:

Cline Center id
80009161957
Albrecht/Koehler/Schutz (CAM) id
CAM-800-1957-09-16

How the match is made is described in crossref-report.md.

Outcome and Target

Coup Atlas research identifies the target as: Plaek Phibunsongkhram (Phibun), Prime Minister of Thailand (overthrown, fled the country).

Baseline coding: Incumbent executive removed from power. Recorded leader fate: deposed; fled the country. The baseline file does not name individual targets; researched names are kept in a separate layer.

Baseline Dataset Citation
Cline Center Coup d’État Project Dataset, v2.2.2
Peyton, Buddy, Joseph Bajjalieh, Michael Martin, and Andrea Gerald. 2026. Cline Center Coup d’État Project Dataset. Cline Center for Advanced Social Research. V.2.2.2. February 17. University of Illinois Urbana-Champaign. doi: 10.13012/B2IDB-9651987_V10
Open dataset DOI ↗
⚑ This citation establishes the coded baseline record; use the claim-level sources above for the researched narrative.

Baseline Source-Document Entries

CSP

Named in the baseline source document; no article citation was recorded.

Luttwak

Named in the baseline source document; no article citation was recorded.

Wikipedia

en.wikipedia.org/wiki/Sarit_Thanarat

New York Times

“Thai Army Seizes Control in Coup; Premier Missing,” September 17, 1957
“PIBUL TO GO TO INDIA Ousted Thai Premier Plans to Stay There After Tokyo Visit,” November 29, 1957

This is the citation trail carried by the baseline dataset, grouped by outlet and rejoined from the line-wrapped original. Coup Atlas has not independently re-checked every document; read the original before citing a specific claim. URLs the import damaged beyond safe repair are shown as plain text and listed in citations-report.md. How this list is built →

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Related Records

Thailand — Military coup, 19581958-10-20SuccessfulSoutheast AsiaThailand — Military coup, 19511951-11-29SuccessfulSoutheast AsiaThailand — Military coup, 19471947-11-08SuccessfulSoutheast Asia