The Socialist Union of Popular Forces (Arabic: الاتحاد الاشتراكي للقوات الشعبية, romanized: Al-Ittihad Al-Ishtirakiy Lilqawat Al-Sha'abiyah; Standard Moroccan Tamazight: ⵜⴰⵎⵓⵏⵜ ⵜⴰⵏⵎⵍⴰⵢⵜ ⵏⵉⵖⴰⵍⵍⵏ ⵉⴳⴷⵓⴷⴰⵏⵏ; French: Union Socialiste des Forces Populaires, USFP) is a social-democratic^[2] political party in Morocco.

The USFP was formed as a breakaway from the National Union of Popular Forces (UNFP), a socialist opposition party which had itself split from the Istiqlal Party in 1959.^[3] The USFP was established in 1975.^[4][5]

The party won the 1997 parliamentary election,^[6] and led the government of Morocco with a centre-left coalition.^[6] During this period, Abderrahmane Youssoufi, who led the USFP, served as the Prime Minister of Morocco.^[6]

In the parliamentary election held on 27 September 2002, the party won 50 out of 325 seats, making it the largest party in the Moroccan parliament. Following those elections, it formed a government with the Istiqlal Party in a three-party coalition known as the "Koutla".

In the next parliamentary election, held on 7 September 2007, the USFP won 38 out of 325 seats, losing 12 seats and becoming only the fifth largest party in parliament.^[7] The USFP was included in the government of Prime Minister Abbas El Fassi, formed on 15 October 2007.^[8]

The USFP is a full member of the Socialist International^[9] and an observer of the Party of European Socialists.^[10]

In the run-up to the November 2011 parliamentary elections, the USFP sought to present a united front with the Party of Progress and Socialism (PPS) and Democratic Forces Front (FFD) to reverse the loss of support for the Moroccan left in the preceding years.^[11] The party placed fifth, with 39 seats, in the 2011 elections.^[12]

The USFP won 34 seats in the 2021 parliamentary election, an increase of 14 seats since the last election.^[13][14]