The United People's Party (Polish: Zjednoczone Stronnictwo Ludowe, ZSL) was an agrarian socialist political party in the People's Republic of Poland. It was formed on 27 November 1949 from the merger of the pro-Communist Stronnictwo Ludowe party with remnants of the independent Polish People's Party of Stanisław Mikołajczyk.

United People's Party Zjednoczone Stronnictwo Ludowe
First leader	Józef Niećko
Last leader	Dominik Ludwiczak
Founded	27 November 1949
Dissolved	27–29 November 1989
Merger of	Polish People's Party Polish People's Party "Nowe Wyzwolenie" People's Party
Succeeded by	Polish People's Party
Headquarters	Grzybowska 4, 00-131 Warsaw
Membership (1989)	300,000
Ideology	Agrarian socialism
Political position	Left-wing
Colors	Green
Politics of Poland Political parties Elections

ZSL became – as intended from its beginning – a satellite party of the Polish United Workers' Party (PZPR), representing the PZPR in the rural areas. It was a member of the Front of National Unity until 1982, and from 1982 it was a member of the Front's successor, the Patriotic Movement for National Rebirth. To keep up the appearance that Poland was ruled by a coalition, the Marshal of the Sejm (parliamentary speaker) was always a member of the ZSL.

In 1989 after victory of the Solidarity trade union in the 1989 Polish legislative elections together with the PZPR's other satellite party, the Alliance of Democrats, ZSL decided to support Solidarity. At the 27–29 November 1989 ZSL congress, ZSL became the Polskie Stronnictwo Ludowe - Odrodzenie ("Polish People's Party - Rebirth"). PSL-Odrodzenie merged with Polish People's Party "Wilanowskie", forming today's Polish People's Party.