1963 Singaporean general election

General elections were held in Singapore on 21 September 1963 to elect all 51 members of the Legislative Assembly. This was the first and only general election held when Singapore was part of Malaysia as an autonomous state, and just days after it became fully independent from the United Kingdom on 16 September following full internal self-government in 1959. It was also the only election to date without any boundary changes to constituencies. The People's Action Party (PAP) under Lee Kuan Yew won 37 of the 51 seats, while 13 went to the Barisan Sosialis (BS) led by Lee Siew Choh, its left-wing splinter party. The United People's Party (UPP) secured one seat through its leader Ong Eng Guan, a former PAP member.

The ruling Alliance Party of Malaysia led by the United Malays National Organisation (UMNO) contested the election through its Singapore branch (SAP) in an attempt to unseat the PAP, straining PAP–UMNO relations. However, the Alliance lost all seven of its seats which they held in Singapore, including those in Malay dominated areas. In response, the PAP contested seats in Peninsular Malaysia during the 1964 federal election the following year, further deepening tensions and mistrust between the Alliance federal government and the PAP state government.

A total of 210 candidates contested the elections, marking the largest slate in Singapore for over six decades until it was surpassed in 2025. The ruling PAP fielded candidates in all 51 seats, while its breakaway parties, BS and the UPP, each put forward 46 and the SAP fielded 42. This was the last election in which any party other than the PAP contested more than half the parliamentary seats. With the two PAP splinter groups and the Alliance fielding nearly full slates, it became one of the most fiercely contested elections and posed a serious challenge to the ruling PAP. Voter turnout reached 95.11%, the highest at the time in Singapore's history.

This was the most recent general election in which the PAP received less than half of the popular vote, at only 47%, and the last parliamentary election to date where MPs (29 out of 51) were elected by a plurality due to the first-past-the-post voting system. It was also the last general election in which an incumbent minister was defeated until 2011 and the last general election in which all seats were contested until 2015. With the Independence of Singapore Agreement 1965, this election was the only one that was held when Singapore was a state of Malaysia. After independence, the elected members of the Legislative Assembly subsequently become members of the inaugural Parliament of Singapore.