The Southeast Asian Games owe its origins to the South East Asian Peninsular Games or SEAP Games. On 22 May 1958, delegates from the countries in Southeast Asian Peninsula attending the Asian Games in Tokyo, Japan had a meeting and agreed to establish a sports organization. The SEAP Games was conceptualized by Luang Sukhum Nayaoradit, then Vice-President of the Thailand Olympic Committee. The proposed rationale was that a regional sports event will help promote cooperation, understanding, and relations among countries in the Southeast Asian region.

​

Six countries, Burma (now Myanmar), Kampuchea (now Cambodia), Laos, Malaya (now Malaysia), Thailand and the Republic of Vietnam (South Vietnam) were the founding members. These countries agreed to hold the Games biennially in June 1959 and the SEAP Games Federation Committee was formed thereafter.

​

The first SEAP Games were held in Bangkok from 12–17 December 1959, with more than 527 athletes and officials from 6 countries; Burma (now Myanmar), Laos, Malaya, Singapore, South Vietnam and Thailand participated in 12 sports.

At the 8th SEAP Games in 1975, the SEAP Federation considered the inclusion of Brunei, Indonesia, and the Philippines. These countries were formally admitted in 1977, the same year when SEAP Federation changed their name to the Southeast Asian Games Federation (SEAGF), and the games were known as the Southeast Asian Games. Despite its location closer to the Pacific archipelago than the Asian continent and not being a member of ASEAN, East Timor was admitted at the 22nd Southeast Asian Games in 2003 Hanoi–Ho Chi Minh City.

​

The 2009 Southeast Asian Games was the first time Laos has ever hosted a Southeast Asian Games (Laos had previously declined to host the 1965 Southeast Asian Peninsular Games citing financial difficulties). Running from 9–18 December, it has also commemorated the 50 years of the Southeast Asian Games, held in Vientiane, Laos.