Founded in 2019 as the merger of the Green Ecological Party – The Greens and Serbian Left, SSP was a member of the Alliance for Serbia (SZS), a coalition of opposition political parties that was initiated by Đilas in 2018. Together with SZS, SSP boycotted the 2020 parliamentary election, claiming that the election would not be free and fair. After the election, SSP became part of the United Opposition of Serbia (UOPS), the successor of SZS. UOPS would be eventually dissolved in January 2021, due to disputes between SSP and the People's Party (Narodna). In late 2021, SSP and Narodna returned together with the Movement of Free Citizens and Democratic Party to form the United for the Victory of Serbia (UZPS) alliance, which was officially formalised in February 2022, to take part in the 2022 general election. The elections resulted in the SSP gaining 10 seats in the National Assembly and 6 seats in the City Assembly of Belgrade. UZPS was also dissolved after the elections. In the 2023 elections, it was part of the Serbia Against Violence alliance.

SSP is a centre-left political party and it serves in opposition to SNS. A self-described anti-corruption party, the party is also opposed to party employment, while regarding economy, SSP has called for tax reforms that would bring in progressive taxation. SSP supports financing free textbooks and school meals for school children, and has called for the introduction of a new labour law. The party supports the accession of Serbia to the European Union, wants Serbia to harmonise its foreign policy with the European Union, and initiate sanctions on Russia regarding the Russian invasion of Ukraine. SSP has criticised Chinese investments into infrastructure and it had adopted a platform in which they pledged "reconciliation, cooperation, and the acceptance of diversity" between countries in the Balkans. Supporters of SSP are pro-European while they also see themselves as socially progressive. SSP is an observer member of the Party of European Socialists.

The Party of Freedom and Justice (SSP) was formed out of the Green Ecological Party – The Greens (ZEP–Zeleni), a political party that was established in 2008. Dejan Bulatović was the leader of ZEP–Zeleni after 2015. He led the party into a coalition with the Greens of Serbia (ZS), which fell apart before the 2017 presidential election, and was a part of the Civic Bloc 381 coalition which was formed in 2018 and headed by the Movement of Free Citizens (PSG). ZEP–Zeleni left the bloc in November 2018. A month later, ZEP–Zeleni joined the Alliance for Serbia (SZS), an opposition political alliance initiated by Dragan Đilas in 2018. A series of anti-government protests began in December 2018 after a physical attack on Borko Stefanović; SZS supported the protests.

In March 2019, it was announced that Đilas agreed with Bulatović to reconstruct the party as SSP with Đilas as the party's president; Đilas previously stated that he had no plans of buying ZEP–Zeleni. Alongside ZEP–Zeleni, the Serbian Left (LS), a political party led by Stefanović, and ten movements and individuals merged to create SSP. The founding convention was held on 19 April 2019, at which Đilas was chosen president, Stefanović as deputy president, and Bulatović and Marinika Tepić as vice-presidents. Following its formation, SSP gained two seats in the National Assembly of Serbia and 13 seats in the City Assembly of Belgrade.

SSP announced that it would boycott the 2020 parliamentary election in September 2019, claiming that the election would not be free and fair. This position was adopted by SZS later that month. Mass protests that began in 2018 formally ended in March 2020 due to the proclamation of the COVID-19 pandemic in Serbia. After the June 2020 parliamentary election, SZS was dissolved and subsequently transformed into the United Opposition of Serbia (UOPS), in which SSP also took part. However, UOPS remained unstable; SSP announced in December 2020 that it would form a joint platform with the PSG regarding the inter-party dialogues on electoral conditions. This was opposed by the People's Party (Narodna), which ultimately led to the dissolution of UOPS in January 2021.

SSP presented its political platform for the inter-party dialogues in February 2021. The dialogues lasted from July to October 2021, though SSP left the dialogues in September 2021 after stating that the proposed document is "unacceptable" (neprihvatljiv), claiming that the document does not offer concrete solutions regarding electoral conditions. After leaving the dialogues, SSP renewed its cooperation with Narodna, which led to the announcement that they would take part in a coalition for the 2022 general election. In November 2021, it was announced that Tepić would be the ballot representative of the joint coalition, which was mainly composed of SSP, Narodna, PSG, and the Democratic Party (DS).

Shortly before the January 2022 constitutional referendum, SSP called for citizens to not take part in the referendum. Later in January 2022, SSP proposed Zdravko Ponoš of Narodna as the presidential candidate of the joint coalition. This coalition was formalised in February 2022 under the name United for the Victory of Serbia (UZPS), when Ponoš was confirmed to be their joint presidential candidate. In the parliamentary election, UZPS won 14% of the popular vote and 10 seats in the National Assembly, while Ponoš won 18% of the popular vote, placing second behind Aleksandar Vučić, the incumbent president of Serbia. Additionally, SSP won 6 seats in the City Assembly of Belgrade in the 2022 Belgrade City Assembly election. Following the elections, Đilas met with Vučić to discuss about the outcome of the Belgrade City Assembly election. This resulted into criticism from Narodna; DS also added that Đilas did not consult with other coalition members before the meeting. This ultimately led to the dissolution of UZPS.

Following the elections, SSP announced that it would form a joint parliamentary group with PSG, Movement for Reversal, and United Trade Unions of Serbia "Sloga" in the National Assembly and City Assembly of Belgrade; these groups were formalised under the name Ujedinjeni. Đilas was re-elected president of SSP in July 2022, while Stefanović, Tepić, and Bulatović retained their positions; Goran Petrović and Dušan Nikezić also became vice-presidents of the party. Bulatović however left SSP and the Ujedinjeni parliamentary group in December 2022, claiming that Tepić allegedly lobbies for the Serbian Progressive Party (SNS). He then met with several government ministers before forming the Alliance of Social Democrats citizens' group in January 2023.

SSP took part in the 2023 mass protests, which began after the Belgrade school shooting and a mass murder near Mladenovac and Smederevo in early May 2023. The Ujedinjeni parliamentary group changed its name to Forward to Europe in July 2023. SSP became part of the Serbia Against Violence (SPN) coalition in October 2023, a coalition of political parties organising the 2023 protests. SPN announced that it will take part in the 2023 parliamentary, Vojvodina provincial, and Belgrade City Assembly elections. Along with Miroslav Aleksić from the People's Movement of Serbia, Tepić was announced as one of the representatives of SPN. In the parliamentary election, SPN won 65 seats, 16 of which went to SSP. After the elections, SPN organised anti-government protests which lasted until 30 December. During the protests, Tepić and other SSP politicians were on a hunger strike.

Once the 14th National Assembly of Serbia was constituted, SSP formed a joint parliamentary group with PSG. This group was dissolved in April 2024, after which SSP formed a parliamentary group on its own. The City Assembly of Belgrade was not constituted because the quorum was not met during the constitutve session. A new election was then called for 2 June. SSP opposed the participation in the new snap election on the grounds that electoral conditions did not improve. This ultimately led to the dissolution of SPN. Parties that decided to take part in the election formed the We Choose Belgrade electoral alliance.

In October 2024, Željko Veselinović and Đorđe Đorđić left the SSP parliamentary group, with Đorđić leaving SSP altogether. They were followed by Sonja Pernat and Irena Živković in November; Veselinović announced the formation of a new political party before 2025.

At the founding convention in April 2019, Đilas stated that SSP would focus on economic prosperity and education, and that it would adopt a declaration of reconciliation regarding the Kosovo issue. This declaration was presented in May 2019, with SSP stating that the declaration "predicts the way to solve the people's life problems [in Kosovo]" (predviđa put rešavanja životnih problema ljudi [na Kosovu]). SSP serves in opposition to SNS. Describing itself as an anti-corruption party, SSP proposed a law regarding the "fight against corruption of public officeholders" (borbu protiv korupcije javnih funkcionera) in November 2019; Tepić noted that the proposal was written on the model of practice of former Romanian anti-corruption prosecutor Laura Kövesi. SSP is also opposed to "party employment" (stranačko zapošljavanje), saying that "it should not matter whether you are a member of a political party, but whether you have the qualifications to do a certain job" (neće biti važno da li ste član stranke, već da li imate kvalifikaciju da radite određeni posao). In July 2022, SSP criticised attacks on investigative journalists.

Ideologically, SSP has been described as a social democratic party, and it is positioned on the centre-left on the political spectrum. Dušan Spasojević, a professor at the Faculty of Political Sciences of University of Belgrade, noted that within the party, Đilas is closer to the political centre, while Tepić is significantly more leftist. Regarding social issues, Spasojević positioned SSP on the centre-left. SSP supported the manifestation of 2022 EuroPride in Belgrade.

SSP criticised the increase on toll fees in June 2019, claiming that the quality of the roads has not improved since 2017, when the toll fees were previously increased. Later in December 2019, SSP presented its proposed law on the origin of property at its party session, which according to Stefanović would confiscate property from those who cannot prove that they acquired it legally. According to its programme from 2020, SSP guaranteed to "implement tax reforms that would introduce a progressive taxation of citizens' income and reduce taxes and contributions to 60% of net earnings" (sprovođenje poreske reforme kojom će se uvesti progresivno oporezivanje dohotka građan i smanjivanje poreza i doprinosa 60% neto zarade), while it also stated its support for abolishing parafiscal taxes and introduce tax reliefs for donations and endowments in health, culture, and sports.

SSP supports financing free textbooks and school meals for school children in Serbia; in September 2022, SSP also said that "with the reduction of corruption and abolishment of unnecessary projects, enough money would be collected to finance free schoolbooks and higher salaries for educators" (ukoliko bi se smanjila korupcije i ukinuli nepotrebni projekti, prikupilo dovoljno para za finansiranje besplatnih udženika i većih plata za prosvetne radnike). SSP has criticised workers' conditions in Serbia and has called for the adoption of a new labour law that would according to SSP "increase wages that could be then used to live with dignity" (omogućiti plate od kojih može da se dostojanstveno živi). Đilas also stated that he is opposed to neoliberalism, calling it "not just wrong, but life-threatening" (neoliberalna ideologija ne samo pogrešna, već i opasna po život).

Critical of duty-free trade with China, SSP has said that it "brings long-term consequences to the Serbian economy, jobs, and working standards".

A pro-European party, SSP supports the accession of Serbia to the European Union, stating that "Serbia's future is in Europe" (budućnost Srbije u Evropskoj uniji). SSP also wants Serbia to harmonise its foreign policy with the European Union and has urged the government to continue the integration of Serbia to the European Union. SSP adopted the "Serbia in the EU until 2030" declaration in March 2023, while a month later it presented its "Forward to Europe" programme, aimed at bringing Serbia closer to the European Union.

Following the beginning of the 2022 Russian invasion of Ukraine, SSP has called for the end of the war in Ukraine, stated its support for the territorial integrity of Ukraine, and has called for humanitarian aid to be sent to the vulnerable population. Initially, SSP opposed to sanctioning Russia, though they reversed this position after the 2022 general elections. Đilas later criticised political neutrality regarding the issue, stating that "neutrality is treated as siding with [Russia]" (politička neutralnost u ovom trenutku se tretira kao svrstavanje uz [Rusiju]"; he also said that Serbia should remain military neutral but with a clear position regarding the war in Ukraine. In November 2022, SSP proposed a resolution that would align Serbia's foreign policy with the European Union and implement sanctions on Russia.

SSP criticised Chinese investments into Serbian infrastructure, claiming that "Serbia became the first Chinese colony in Europe" (Srbija prva kineska kolonija u Evropi). Regarding Belgrade, SSP stated its support for the termination of the contract with the investor of Belgrade Waterfront in April 2021. SSP called for the end of "environmental massacre" (ekološki masakr) in Aleksinac in May 2019, claiming that the trees in the centre of Aleksinac were cut down illegally. SSP criticised the ministry of environmental protection regarding the quality of air in Bor in June 2019, claiming that the government ignored excessive air pollution with sulfur dioxide and heavy metal particles.

Regarding regional cooperation, SSP has adopted a platform in which they pledged reconciliation, cooperation, and the acceptance of diversity between countries in the Balkans. SSP condemned the Srebrenica genocide, stating that "11 July should be the remembrance of the Srebrenica victims" (11. jul treba da bude posvećen srebreničkim žrtvama), and that "the Balkans should function on the principles of tolerance and cooperation" (Balkan koji funkcioniše na principima tolerancije i saradnje).

SSP has criticised the approach of the Serbian government towards Kosovo and the Kosovo government of Albin Kurti, opting to solve the Kosovo issue via dialogue. In its declaration regarding Kosovo, SSP advocated for reconciliation between Serbs and Albanians. Jelena Milošević, an SSP member of parliament, claimed that Kurti's government is authoritarian and violated rights of Kosovo Serbs. During the North Kosovo crisis in 2022, SSP supported the resignation of Kosovo Serbs from the institutions of the government of Kosovo.

According to a Heinrich Böll Foundation research from November 2020, supporters of SSP saw themselves as socially progressive and economically leftist. The researchers also noted that voters with more liberal preferences were also orientated towards SSP. Spasojević noted in 2022 that its supporters closely represented the views of Tepić than Đilas, while he also noted that its voters are pro-European.

SSP is led by Dragan Đilas, who was most recently re-elected in 2022. Additionally, Stefanović serves as the party's deputy president, while Tepić, Nikezić, and Petrović serve as vice-presidents of SSP. Alongside them, Velibor Pavlović serves as the president of the party's executive board, Peđa Mitrović serves as the general-secretary of SSP, and Ana Stevanović serves as the international secretary of SSP. Its headquarters is located at Vojvode Stepe 199 in Belgrade. SSP has a youth wing named the SSP Youth and a women's wing named Women's Network.

Đilas met with Zoran Zaev, the president of the Social Democratic Union of Macedonia, in February 2019 with whom he discussed cooperation between SSP and Zaev's party. As the representative of SSP, Đilas took part in a meeting that was organised by the Party of European Socialists (PES) in May 2020, where he expressed his party's position regarding the 2020 parliamentary election and European Union. In November 2022, SSP formed connections with the Social Democratic Party of Austria which stated its support for SSP to be admitted into PES. As the representative of SSP, Tepić took part in the Global Progressive Forum which was organised by PES in December 2022. SSP became an observer member of PES in November 2023.

In the Parliamentary Assembly of the Council of Europe, SSP is represented by Tatjana Pašić, who sits in the Socialists, Democrats and Greens Group, while in the Congress of Local and Regional Authorities, SSP was previously represented by Marko Dimić, who was a substitute and sat as a "non-registered" member.

#		President		Birth–Death	Term start	Term end
1		Dragan Đilas		1967–	19 April 2019	Incumbent

National Assembly of Serbia

Year	Leader	Popular vote	% of popular vote	#	# of seats	Seat change	Coalition	Status	Ref.
2020	Dragan Đilas	Election boycott			0 / 250	2	SZS	Extra-parliamentary
2022		520,469	14.09%	2nd	10 / 250	10	UZPS	Opposition
2023		902,450	24.32%	2nd	15 / 250	5	SPN	Opposition

Graphs are unavailable due to technical issues. Updates on reimplementing the Graph extension, which will be known as the Chart extension, can be found on Phabricator and on MediaWiki.org.

Assembly of Vojvodina

Year	Leader	Popular vote	% of popular vote	#	# of seats	Seat change	Coalition	Status	Ref.
2020	Dragan Đilas	Election boycott			0 / 120	0	SZS	Extra-parliamentary
2023		215,197	22.55%	2nd	9 / 120	9	SPN	Opposition

City Assembly of Belgrade

Year	Leader	Popular vote	% of popular vote	#	# of seats	Seat change	Coalition	Status	Ref.
2022	Dragan Đilas	195,335	21.78%	2nd	6 / 110	7	UZPS	Opposition
2023		325,429	35.39%	2nd	9 / 110	3	SPN	Snap election
2024		Election boycott			0 / 250	9	–	Extra-parliamentary	–

Graphs are unavailable due to technical issues. Updates on reimplementing the Graph extension, which will be known as the Chart extension, can be found on Phabricator and on MediaWiki.org.

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