1963 Singaporean general election

General elections were held in Singapore on 21 September 1963, five days after Singapore became part of Malaysia. Voters elected all 51 members of the Legislative Assembly. The elections were the only ones to date with no boundary changes to any existing constituencies prior to the elections. The result was a victory for the People's Action Party (PAP), which won 37 of the 51 seats, while the majority of the remaining seats were won by Barisan Sosialis (BS).

The ruling federal government of Malaysia, the United Malays National Organisation (UMNO), contested the elections as part of the Singapore Alliance Party (SAP) in an attempt to oust the PAP, straining relations between the two parties. The Alliance lost all seven seats which it held prior to the elections. Their participation in the elections prompted the PAP to contest seats outside Singapore and in Peninsular Malaysia in the next federal election held in 1964, further adding to more tensions between the UMNO federal government and the PAP state government.

A total of 210 candidates contested the elections, making it the largest slate of candidates to contest ever in Singapore's history for more than six decades until 2025. The ruling PAP fielded 51 candidates, its breakaway parties BS and UPP fielded 46 candidates each, and the Alliance, the Singapore branch of the Malaysian federal ruling coalition, fielded 42 candidates. This also marked the last time that any other party than the PAP would field candidates in more than half the total parliamentary seats. With two breakaway factions of the PAP fielding nearly full slate of candidates, this was the most hard fought election in Singapore's history and particularly for the ruling PAP.

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. As Singapore would gain independence in 1965, the elections were the only ones 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.