Singapore, officially the State of Singapore, was one of the 14 states of Malaysia from 16 September 1963 to 9 August 1965. Singapore was previously a British colony, which was originally part of the Straits Settlements. As part of Malaysia, Singapore was the smallest state with a land area of 581.5 km2 (224.5 sq mi) but had the largest population of 1.82 million.
Malaysia was formed on 16 September 1963 through the merger of the Federation of Malaya with the former British colonies of North Borneo (Sabah), Sarawak and Singapore. The merger was supported by the British, Malayan and Singaporean leaders as a measure to counter communist influence in Southeast Asia. Through the 1962 integration referendum and the Malaysia Agreement, Singapore was given higher autonomy in education and labour, with the Federal Government in Kuala Lumpur overseeing defence and external affairs. Singapore was allocated only 15 seats in the Dewan Rakyat, and a reciprocal arrangement prevented citizens on either side from voting or contesting in the other's elections. These constitutional rules ensured the island's autonomy while limiting the influence of Singapore's Chinese-majority population on national politics.
However, political, racial and economic conflicts soon emerged between the governments of Singapore and Malaysia, led by the People's Action Party (PAP) and the Alliance Party respectively. Despite the agreement, both sides contested in each other's arenas: the Singapore branch of the Alliance in 1963, and the PAP in 1964. Furthermore, communal tensions between the Malay and Chinese populations in Singapore led to race riots later that year. The PAP's criticisms of the Federal Government's tax proposals in 1964 and the delay in Sabah development loans led to threats to raise Singapore's revenue contribution from 40 to 60 per cent. Despite negotiations at constitutional rearrangements, Malaysian prime minister Tunku Abdul Rahman opted to resolve the disagreements by separating Singapore from the Federation, a decision supported by Singapore's finance minister Goh Keng Swee and a few PAP leaders. The Separation Agreement was signed on 7 August 1965, and Singapore became a sovereign state on 9 August.
Following separation, Malaysia supported Singapore's entry into the United Nations and the British Commonwealth. Both nations continued to share a national carrier, Malaysian Airways – renamed Malaysia–Singapore Airlines in 1966 – until the airline's split in 1971. The Singapore dollar and the Malaysian ringgit, along with the Brunei dollar, were also interchangeable with each other under the Currency Interchangeability Agreement until Malaysia withdrew in 1973. The historical narrative, particularly in Singapore due to limited public information, taught that the country had been abruptly expelled from Malaysia. This perception was shaped by a lack of detail regarding the separation talks and the sudden announcement of independence. The public release of the Albatross file in December 2025, containing Goh's records of the negotiations, provides a fuller account.
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