The Democratic Party , abbreviated as DP, was a political party in Japan. It was the largest opposition political party in Japan from 2016 until its marginalization in the House of Representatives in 2017. The party was founded on 27 March 2016 from the merger of the Democratic Party of Japan and the Japan Innovation Party. The majority of the party split on 28 September 2017, before the 2017 general election, with many its members contesting the election as candidates for the Party of Hope, Constitutional Democratic Party of Japan or as party members without nomination. On 7 May 2018 the DP merged with the Party of Hope to form the Democratic Party For the People.

The Democratic Party of Japan was a centrist to centre-left liberal or social-liberal political party in Japan from 1998 to 2016.