The 1957 Singapore City Council elections were the first in which all council seats were filled through direct popular vote, following the removal of appointed positions. Nomination Day was held on 18 November 1957, and polling took place on 21 December. A total of 32 seats were contested. For the first time, the office of Mayor of Singapore was introduced, to be awarded to the leader of the political party that secured the largest number of seats.
The People's Action Party (PAP) won the most seats with 13, although it did not achieve a majority. The Liberal Socialist Party (LSP) received the highest share of the popular vote but secured only 7 seats. As the party with the largest number of seats, the PAP was offered the mayoralty and nominated Ong Eng Guan to the post. He became the first and only elected mayor in Singapore's history.
Under First-past-the-post voting, six candidates (out of the 14 multi-cornered contests) are elected to the council with under a simple majority (50%) of the valid votes cast. The results for Sepoy Lines came with then a record of the narrowest election margin to date at about 0.4%, which would later be surpassed by the River Valley Constituency's 0.05% margin in the 1959 Singaporean general election, two years later. PAP's Chan Choy Siong in Kreta Ayer won the best margin in the election with 86.8% of the votes cast, while the worst-performing candidate for the election was T. R. Fernandez, who garnered 258 votes, 4.2% of the valid votes cast in Delta. Only four candidates had garnered under 12.5% of their vote share and had their $250 election deposit forfeited.