The Sardinian Socialist Action Party (Italian: Partito Sardo d'Azione Socialista, PSd'AzS) was a regionalist social-democratic political party active in Sardinia. The party was founded in 1948 by a split from the Sardinian Action Party led by Emilio Lussu, former member of the "Sassari brigade" during the Italian resistance movement. The party won 6.6% in the first regional election in 1949 and shortly after merged with the Italian Socialist Party, a party of which Lussu was a senator until 1963.