The Social Democratic Union of Macedonia (Macedonian: Социјалдемократски сојуз на Македонија – СДСМ, Socijaldemokratski sojuz na Makedonija – SDSM, Albanian: Lidhja socialdemokrate e Maqedonisë – LSDM) is a social democratic[1] political party, and the main centre-left[2] party in North Macedonia.

The Social Democratic Union of Macedonia is a member of the Progressive Alliance and an associate affiliate of the Party of European Socialists (PES).

The party supported a practical solution to the Macedonia naming dispute with Greece, which succeeded under the Prespa Agreement.

Its roots can be traced to 1943 upon the formation of the Communist Party of Macedonia (CPM) during World War II in the Democratic Federal Yugoslavia.

[4][5] Unlike its rival VMRO-DPMNE, the party has traditionally had support from the urban middle-classes, the former Yugoslav managerial elite and the former nomenklatura.

[10] During 1997 and the first half of 1998, Crvenkovski and his governing centre-left coalition were criticised by the public due to the high unemployment rates (42 per cent in 1997 and 41 per cent in 1998), rampant corruption, insider privatization, dysfunctionally high levels of taxation, failure to attract foreign investment, and the slow pace of reforms aimed at giving ethnic Albanians, Turks, and Roma people equal status with ethnic Macedonians.

[6] The party was defeated in the 2006 parliamentary elections, with the main reasons being the high rate of unemployment, corruption scandals, and concessions in favour of the Albanians taken to implement the Ohrid Framework Agreement.

From February to May 2015, Zaev released wiretapped material that incriminated Prime Minister Nikola Gruevski for illegally spying on more than 20,000 citizens.

Large crowds gathered to protest on May 17, demanding resignation from Gruevski, who refused to step down and organized a pro-government rally the following day.

The political crisis was resolved with the Pržino Agreement in July 2015, which obliged a resignation from Gruevski, participation of SDSM in the ministries, and early parliament elections.

[14] After its defeat in the 2021 local elections in North Macedonia when it lost 57 municipalities,[18] Zaev stepped down as the party's president.