The Polish United Workers' Party (PUWP; in Polish, Polska Zjednoczona Partia Robotnicza, PZPR), was the governing political party in communist-ruled Poland from its creation (through a fusion of the communist Polish Workers' Party and the left wing of the Polish Socialist Party) in December 1948 until the regime's electoral defeat in 1989.

In January 1990 the party reconstituted itself as the Social Democracy of the Republic of Poland (Socjaldemokracja Rzeczypospolitej Polskiej, SdRP), since April 1999 the principal constituent of the Alliance of the Democratic Left (Sojusz Lewicy Demokratycznej, SLD).

The PUWP's principal leaders were:

For SLD website (in Polish), see