The Democratic Party (DP; Korean: 민주당; Hanja: 民主黨; RR: Minjudang; MR: Minjutang) was a liberal political party in South Korea.

Formerly named the United Democratic Party (UDP; Korean: 통합민주당; Hanja: 統合民主黨; RR: Tonghapminjudang), it was the main opposition party in the 18th Assembly.

As a result of the 2004 Parliamentary election, the party won an outright majority in the National Assembly by winning 152 of 299 seats.

It was the first time in over 40 years that a centre-left party had won a majority in the legislature.

In local elections 2010, the Democratic Party scored a victory in eight mayoral and gubernatorial posts, including the Inchon mayorship.