You Si-kun, also romanized Yu Shyi-kun, is a Taiwanese politician. He was one of the founding members of the Democratic Progressive Party (DPP), and is known to be a strong advocate of Taiwan independence. He led the DPP as chairman from 2006 to 2007 and served as Premier from 2002 to 2005.

The Democratic Progressive Party (DPP) is a Taiwanese nationalist and centre to centre-left political party in Taiwan. It is currently the major ruling party in Taiwan, controlling both the presidency and the central government, also the dominant party in the Pan-Green Coalition.