The Serbian Radical Party (Serbian: Српска радикална странка, Srpska radikalna stranka, SRS) is a radical nationalist political party in Serbia, founded in 1991. Currently the second-largest party in the Serbian National Assembly, it has branches in three of the nations that currently border Serbia – all former federal republics of Yugoslavia. The party is registered as the Party of Serb Radicals in Montenegro, the Serbian Radical Party of the Republika Srpska in Bosnia and Herzegovina, and the Radical Party of the Serbs in Macedonia. It was active in the Republika Srpska and in the early 1990s founded the Party of Danube Serbs in the Republic of Serbian Krajina, which later broke its ties with the SRS.
Vojislav Šešelj led the party as president during and after the Bosnian War before surrendering to the International Criminal Tribunal for the former Yugoslavia (ICTY) in 2003 to stand trial for alleged war crimes. Deputy president Tomislav Nikolić took over as de facto leader and supported the accession of Serbia to the European Union, which Šešelj and his faction continued to oppose. Nikolić and his faction resigned from the party in 2008 over this disagreement, and went on to launch the Serbian Progressive Party (SNS).
The party's core ideology is based on Serbian nationalism, and it subscribes to the idea of Greater Serbia which, according to Šešelj, is the raison d'être of the party. The party also describes itself as anti-globalist, and wants to abandon Serbian attempts to become a member of the European Union. Instead, it aims to establish pan-Slavic "brotherly" ties with Russia, as well as ties with China, and to unite all Balkan Serbs into a single country. In 2007 it advocated the use of force to block the independence of Kosovo. The party remains loyal to the legacy of late President Milošević, and would bring an end to searches for fugitives wanted by the ICTY such as Ratko Mladić and Radovan Karadžić; the party regards both to be "Serbian heroes".
Under the leadership of Nikolić the party steered more towards the centre of Serbian politics, focusing on social issues such as unemployment and poverty rather than militant nationalism. Nikolić and his supporters eventually broke away from the party in 2008 due to his support for the accession of Serbia to the European Union, which conflicted with the position of Šešelj's group who thereafter maintained the party's hardline ideology.
The SRS has maintained ties with Vladimir Zhirinovsky and his Liberal Democratic Party of Russia, as well as France's Jean-Marie Le Pen and his National Front.