The Social Democratic Party (Catalan: Partit Socialdemòcrata, PS) is a social-democratic^[2] political party in Andorra.

The party was established in the run-up to the March 2001 parliamentary elections when the National Democratic Group split in two, with the Democratic Party also being formed.^[4] The new party received 28.7% of the vote and won six seats.^[5]

In the buildup to the April 2005 parliamentary elections the party formed an alliance named L'Alternativa with the Parochial Union of Independents Group (GUPI) and Democratic Renewal to contest parish-level seats.^[5] The party won six seats at the national level, whilst the alliance won six seats at the parish level. With a total of twelve seats, the party remained in opposition.

The April 2009 parliamentary elections saw the party renew its alliance with GUPI and some independents.^[6] The alliance won 14 of the 28 seats and PS leader Jaume Bartumeu became Prime Minister, with the Andorra for Change party supporting the government.^[7]

In 2010 the APC withdrew its support for the PS-led government, and in 2011 the General Council rejected the government's budget, forcing early elections.^[7] The April 2011 parliamentary elections saw the PS receive 34.8% of the vote, reducing its representation to six seats.^[7]

In the March 2015 parliamentary elections, the party ran in alliance with the Greens of Andorra, Citizens' Initiative and independent candidates. The alliance's vote share fell to 24%, winning only three seats.

Some notable past and present members are:

• Jaume Bartumeu, Prime Minister from 2009 to 2011
• Carles Blasi Vidal
• Josep Dallerès Codina
• Jordi Font Mariné
• Pere López Agràs, Prime Minister 2011
• Maria Pilar Riba Font, sat on General Council from 2005 to 2011