The Social Democratic Party (Romanian: Partidul Social Democrat, PSD) is the largest political party in Romania. It is also the largest social democratic political party in the country. It was founded by Ion Iliescu, Romania's first democratically elected president at the 1990 Romanian general election.
It is a member of the Progressive Alliance (PA), which was founded in 2013, Socialist International (SI), and the Party of European Socialists (PES). As of 2015, the PSD had 530,000 members.