Sin Chung-kai (Chinese: 單仲偕; born 15 June 1960) is a former member of the Hong Kong Legislative Council.

In 1982, Sin obtained his bachelor's degree at the University of Hong Kong, where he served as the Current Affairs Secretary of the Student Union.

[5] In 2014, Sin participated in the by-election for the South Horizons West constituency, where he got 22.9% of the votes and lost to Judy Chan from the NPP.

[8] In 1995, Sin ran the Hong Kong legislative election for the New Territories South constituency, winning dominantly with 70.74% of the votes over two other candidates.

[9] Sin served as an executive committee member in the United Democrats of Hong Kong (UDHK) between the years 1990–1994.

[14] During his political career, Sin had advocated for human rights, economic prosperity, and free flow of information in Hong Kong.

[17][18] On 10 June 2022, Sin, along the two other pro-democracy figures, had his Silver Bauhinia Star honour removed, and his Justice of the Peace appointment was revoked by the government due to his jail sentences related to anti extradition-bill protests.