The Social Democratic Party of Austria (, SPÖ) is a social-democratic political party in Austria. The oldest extant political party in Austria, the SPÖ is a member of the Socialist International, Progressive Alliance and Party of European Socialists. Before adopting the current title in 1991, the SPÖ was named Social Democratic Workers' Party of Austria (Sozialdemokratische Arbeiterpartei Österreichs, SDAPÖ) from 1888 to 1945 and, later, Socialist Party of Austria (Sozialistische Partei Österreichs) until 1991.