Teo Kok Seong (; born 18 October 1979) is a Malaysian politician who has served as Member of the Negeri Sembilan State Executive Council (EXCO) in the Pakatan Harapan (PH) state administration under Menteri Besar Aminuddin Harun and Member of the Negeri Sembilan State Legislative Assembly (MLA) for Bahau since May 2018 and from March 2008 to May 2013. He is a member of the Democratic Action Party (DAP), a component party of the PH and formerly Pakatan Rakyat (PR) and Barisan Alternatif (BA) coalitions. He has served as Member of the Central Executive Committee (CEC) of DAP since March 2022. He also served as the Youth Chief of DAP or known as the Chief of the youth wing of DAP namely the DAP Socialist Youth (DAPSY) from December 2012 to November 2015.
Political career He joined DAP in 2002. In March 2015, he was arrested for his involvement in the "Kita Lawan" rally. In 2008 he was elected to the Negeri Sembilan State Legislative Assembly for the seat of the Bahau and he won election to the federal parliament for the constituency of Rasah in 2013. In 2018 election he switched seat to Bahau and he defeated BN's candidate and PAS's candidate with a majority of 6109 votes. During the 2026 elections, due to the loss of PH constituencies in Chennah, Klawang, Pilah and Repah, he is the sole non BN-PN representative east of Seremban.
Election results + Negeri Sembilan State Legislative Assembly Percentage figures based on total turnout. Results only available from the 2004 election.YearConstituencyCandidate VotesPctOpponent(s)VotesPctBallots castMajorityTurnout2008N08 Bahau (DAP)6,18852.24%Lim Fui Ming (MCA) 5,35145.17%11,846837 72.84%2018 (DAP) 10,09464.74% Chong Wan Yu (MCA)3,98525.56%15,5916,10981.11% (PAS)1,5129.70%2023Teo Kok Seong (DAP)11,93977.18%Kumar S Paramasivam (PAS) 3,53122.82%15,6028,40860.55%
+ Parliament of MalaysiaYearConstituencyCandidateVotesPctOpponent(s)VotesPctBallots castMajorityTurnout2013P130 Rasah (DAP)48,96465.77%Teo Eng Kian (MCA) 25,47934.23%75,86023,48585.81%
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