Ong Eng Guan (Chinese: 王永元; pinyin: Wáng Yǒngyuán; 1925–2008) was a Singaporean politician who served as Minister for National Development between 1959 and 1960.

Ong's anti-colonial stance shocked the British government and every City Council meetings then were considered entertainment for the spectators there.

Ong continued to run the City Council from December 1957 till April 1959 when he resigned to contest in the first fully elected Legislative Assembly.

In June 1960, Ong tabled 16 resolutions to the Central Executive Committee that challenged the party leadership, after which he was sacked from the cabinet and expelled from the PAP.

He then stood as an independent in the by-election held in April and won the seat due to his popularity in the Chinese community.