Southeast Asia Treaty Organization

Not to be confused with South East Asia Cultural Organisation or Association of Southeast Asian Nations.

Southeast Asia Treaty Organization
AbbreviationSEATO
Formation8 September 1954
Dissolved30 June 1977
TypeIntergovernmental military alliance
HeadquartersBangkok, Thailand
Region served
Southeast Asia
Membership
8 states

Non-members protected by SEATO
3 states
Official languages
6 languages

The Southeast Asia Treaty Organization (SEATO) was an international organization for collective defense in Southeast Asia created by the Southeast Asia Collective Defense Treaty signed in September 1954 in Manila, Philippines. The formal institution of SEATO was established on 19 February 1955 at a meeting of treaty partners in Bangkok, Thailand. The organization's headquarters was also in Bangkok. A total of eight members joined the organization in its lifetime.

Primarily created to block further communist gains in Southeast Asia, SEATO is generally considered a failure, as internal conflict and dispute hindered general use of the SEATO military; however, SEATO-funded cultural and educational programs left longstanding effects in Southeast Asia. SEATO was dissolved on 30 June 1977, after many of its members lost interest and withdrew.