The Party of Democratic Socialism (KODISO; Greek: Κόμμα Δημοκρατικού Σοσιαλισμού (ΚΟΔΗΣΟ), Komma Dimokratikou Sosialismou) is a former centre-left political party in Greece founded in 1979 by former members of the Union of the Democratic Centre (EDIK).

In the 1981 European Parliament election, it earned a seat for its president Yagos Pesmazoglou.

The party was noted for its pro-European Union stance.

[1] In the 1984 European Parliament election, the party won 0.8% of the vote and Pesmazoglou resigned.

Shortly before the 1985 legislative election, the withdrawal of Sotiris Kouvelas and Virginia Tsouderou led the party to participate with New Democracy.