The Socialist Party of Serbia (Serbian: Социјалистичка партија Србије, romanized: Socijalistička partija Srbije, abbr.

SPS was founded in 1990 as a merger of the League of Communists of Serbia and Socialist Alliance of Working People of Yugoslavia with Slobodan Milošević as its first president.

The Democratic Opposition of Serbia coalition defeated SPS in the 2000 general elections but Milošević declined to accept the results.

Although it described itself as a democratic socialist party, SPS promoted mixed economy and populist nationalism under Milošević's leadership and was accused of authoritarianism.

[10][12] According to political scientist Jerzy Wiatr, the merger "did not substantially change either the organisational structure of the party or its administration", although SPS did gain control of a large amount of infrastructure, including material and financial assets.

[23][24] With the opposition boycotting the May 1992 parliamentary election, due to claiming that there were no free and fair electoral conditions,[17]: 84–85  SPS won 49% of the popular vote.

[41] Vuk Drašković, the leader of SPO, supported the proposed Rambouillet Agreement, though Milošević declined to sign it, which ultimately led to the NATO bombing of Yugoslavia.

[41] SPS suffered defeat and only won 37 out of 250 seats in the National Assembly, which put the party in opposition for the first time since its formation in 1990.

[46] Milošević, who was still the president of SPS, was arrested in March 2001 on suspicion of corruption and abuse of power, and was shortly after extradited to the International Criminal Tribunal for the former Yugoslavia to stand trial for war crimes instead.

[56][57] A month later, SPS took part in a snap parliamentary election in which it won 22 seats; the drop in popularity occurred due to their voters shifting towards SRS.

[70][71]: 153–154  The DS–SPS coalition government was sworn in July 2008, with Dačić serving as first deputy prime minister while Slavica Đukić Dejanović became the president of the National Assembly.

[70][71]: 155 While in government, SPS was faced with challenges regarding the Kosovo declaration of independence and the global financial crisis, which led to low rates of economic growth.

[83]: 19 [84] SPS remained in government, although Dačić was succeeded by Aleksandar Vučić, the leader of SNS, as prime minister of Serbia.

[87][94] Following the election, SPS agreed to again serve as a junior member in the SNS-led coalition government, which was inaugurated in August 2016.

[106] SPS remained in government with SNS after the election, while Dačić, who had been the first deputy prime minister of Serbia since 2014, became the president of the National Assembly in October 2020.

[111][112] In the parliamentary election, SPS took part in a coalition with JS and Zeleni, while it campaigned on greater cooperation with China and Russia.

[115][116] SPS agreed to continue governing with SNS after the election, which led to Dačić being re-appointed as first deputy prime minister in October 2022.

[117][118] After Vučić announced the formation of the People's Movement for the State in March 2023, Dačić has affirmed that it could bring "a new, even higher stage of cooperation between SNS and SPS".

[125][126] In an unprecedent move, SPS formed a joint electoral list with SNS for the 2024 Belgrade City Assembly election.

[128] SPS adopted its first political programme in October 1990, which had the intention to develop "Serbia as a socialist republic, founded on law and social justice".

[11]: 64 [16]: 206  The party made economic reforms outside of Marxist ideology such as recognising all forms of property and intended a progression to a market economy while at the same time advocating some regulation for the purposes of "solidarity, equality, and social security".

[132] Political scientists Heinz Timmermann and Luke March, and Marko Stojić, a Metropolitan University Prague lecturer, associated SPS during Milošević's era with nationalist form of populism.

[45]: 399 [138] Warren Zimmermann, the last United States ambassador to Yugoslavia, argued that Milošević was "not a genuine nationalist but an opportunist".

[140] Though shortly before the Dayton Agreement in 1995, SPS began to oppose the government of Republika Srpska, which was headed by Radovan Karadžić.

[151] Since then, SPS had adopted its support for the accession of Serbia to the European Union,[146]: 67  and a more pro-European image after it came back to government in 2008,[18]: 151  which scholars Nataša Jovanović Ajzenhamer and Haris Dajč described as rather pragmatic.

[17]: 64  According to political scientist Dragomir Pantić, supporters of SPS in the early 2000s were mostly elderly people, traditionalists, and those without higher education.

[156] The Heinrich Böll Foundation conducted a research in November 2020 in which most SPS supporters were against the accession of Serbia to the European Union, preferred closer relations with Russia instead, and wanted to implement laws to preserve patriarchal family values.

[169] Following the 2008 elections, SPS sent an application to join the Socialist International while Dačić also met with its then-president George Papandreou.

[170][171] However, the Social Democratic Party of Bosnia and Herzegovina opposed this move and called for its application to be declined, while Jelko Kacin, a Liberal Democracy of Slovenia politician, claimed that Tadić blocked SPS from joining the Socialist International.

[174] In the Parliamentary Assembly of the Council of Europe, SPS is represented by Dunja Simonović Bratić, who sits in the Socialists, Democrats and Greens Group.