The Communist Party of Denmark is a communist party in Denmark. The DKP was founded on 9 November 1919 as the Left-Socialist Party of Denmark, through a merger of the Socialist Youth League and Socialist Labour Party of Denmark, both of which had broken away from the Social Democrats in March 1918. The party adopted its present name in November 1920, when it joined the Comintern.

The Red–Green Alliance or Unity List is an eco-socialist political party in Denmark. It was founded in 1989 with the merger of three Marxist parties and it is the most left-wing party in the Parliament of Denmark, where it advocates for the expansion of the welfare state and social justice as well as the socialist transformation of Denmark and the entire globe. During the 2021 Copenhagen City Council election the party placed first, with 24.6% of the votes. The party is also active in various trade unions within Denmark.