Lim Chin Siong (Alternative spelling: Lim Ching Siong; Chinese: ???; pinyin: LÃn Qing Xiáng; Pe?h-oe-ji: Lîm Tshinn-siông; 28 February 1933 – 5 February 1996) was a leftwing politician and trade union leader in Singapore in the 1950s and 1960s.
He co-founded the People's Action Party in 1954, and galvanised many trade unions in support of the party with his popularity.
He remains the youngest parliamentarian of Singapore to be elected.
However, Lim's political career was cut short by two detentions without trial after being labelled a Communist: first, in 1956 to 1959, when under Lim Yew Hock he was arrested; and second, from 1963 to 1969, under Operation Coldstore.
He was released in 1969 after he attempted suicide in prison, on the condition that he renounce politics for good.