The Spanish Socialist Workers’ Party (Partido Socialista Obrero Español), or PSOE, is a social democratic political party in Spain. Founded in 1879, the PSOE is Spain’s oldest existing political party and has governed longer than any other party in modern democratic Spain. The party was led in 2026 by Prime Minister Pedro Sánchez, who has served since 2018 and forms a coalition government with the left-wing Sumar party, established in November 2023. The PSOE is a member of the Party of European Socialists, the Progressive Alliance, and the Socialist International, representing center-left social democratic politics in Spain.