This was the only year in Singapore history where a third round of by-elections was held, after yet another spate of resignations by Barisan Members of Parliament. This time, they were officially sanctioned by Barisan in tandem with its boycott of Parliament and "struggle for democracy". The remaining MPs would resign, starting with Chia Thye Poh and Lee Tee Tong on 7 October 1966. On 29 October 1966, Chia was detained under the Internal Security Act. For refusing to admit to and renounce his alleged communist links, he was kept for 23 years and became the world's second-longest political prisoner after former South African president Nelson Mandela. Lee had been detained for nearly three years and was released in 1981, after 17 years. Also, PAP MP Fong Kim Heng requested to retire from 18 October 1966 due to poor health. Once again, the seats were conceded to PAP via walkovers. Ho Kah Leong was the youngest MP Singapore had until 2011.

Writ of election: 27 October 1966 [Thu]
Nomination day: 2 November 1966 [Wed]
Members swearing-in: 5 December 1966 [Mon]

Electorate: 39,371

Election deposit: $500

Bukit Timah Joo Chiat Jurong

General Election 1963
By-Election 1965
By-Election January 1966
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Next: By-Elections 1967
General Election 1968