Social Democratic Party (Portugal)

The Social Democratic Party (Portuguese: Partido Social Democrata [pɐɾˈtiðu susiˈal dɨmuˈkɾatɐ], PSD) is a liberal-conservative political party in Portugal that is currently the country's ruling party. Commonly known by its colloquial initials PSD, on ballot papers its initials appear as its official form PPD/PSD, with the first three letters coming from the party's original name, the Democratic People's Party (Partido Popular Democrático, PPD). A party of the centre-right, the PSD is one of the three major parties in Portuguese politics, its rivals being the Socialist Party (PS) on the centre-left and the far-right Chega (CH) party.

The PSD was founded in 1974, two weeks after the Carnation Revolution. In 1976, the party adopted its current name. In 1979, the PSD allied with centre-right parties to form the Democratic Alliance and won that year's election. One year later, the party's founder and then Prime Minister, Francisco Sá Carneiro died in a plane crash. After the 1983 general election, the party formed a grand coalition with the Socialist Party, known as the Central Bloc, before winning the 1985 general election under new leader Aníbal Cavaco Silva, who shifted the party to the right. Cavaco Silva served as Prime Minister for ten years, instituting major economic liberalisation and winning two landslide victories. After he stepped down, the PSD lost the 1995 election. The party was returned to power under José Manuel Durão Barroso in 2002, but was defeated in the 2005 election. The party was able to return to power after the 2011 elections and four years later was able to win a plurality in the 2015 legislative election, winning 107 seats in the Assembly of the Republic in alliance with the CDS – People's Party, but being unable to form a minority government and went back to the opposition. Nine years later, in 2024, the party returned to power as a minority government, under a rebranded Democratic Alliance coalition, alongside CDS–PP and the People's Monarchist Party (PPM), a mandate that was renewed in May 2025. The party elected its current leader, Luís Montenegro, on 28 May 2022. Since the 2024 election, Montenegro has been the incumbent Prime Minister of Portugal.

Originally a social democratic party, the PSD became the main centre-right, conservative party in Portugal. The PSD is a member of the European People's Party and the Centrist Democrat International. Until 1996, the PSD belonged to the European Liberal Democrat and Reform Party and Liberal International. The party publishes the weekly Povo Livre (Free People) newspaper.