The Socialist Party of Senegal (Parti Socialiste du Sénégal, PS) is a political party in Senegal. It was the ruling party in Senegal from independence in 1960 until 2000. Ousmane Tanor Dieng has been the First Secretary of the party since 1996. The best-known figure of the PS was the late poet and president, Léopold Sédar Senghor.
In the 2000 presidential election, the party's candidate, long-time president Abdou Diouf, was defeated by the leader of the Senegalese Democratic Party, Abdoulaye Wade, in a second round of voting. Diouf received the most votes, 41.3%, in the first round, but in the second round he received only 41.51% against Wade. In the parliamentary election held on 29 April 2001, the party won 17.4% of the popular vote and 10 out of 120 seats. Tanor Dieng was the party's candidate in the February 2007 presidential election; he took third place with 13.56% of the vote. The party participated in a boycott of the June 2007 parliamentary election.