The Social Democrat Party () was a short-lived social democratic political party in the Ottoman Empire, founded in the aftermath of the First World War. Notable members included Mehmet Esat Ià Âñk, Ata Atalay, Osman Nuri Eralp, Samipaà Âazade Sezai, Hamdi Bey, Yorgaki Efendi, Ubeydullah Bey, and Besim ÃÂmer Akalñn.
It was a member of the Second International. It sent a representative to the Sultanate Council, a faux-parliament organized by Mehmed VI and Damat Ferid Pasha in between the dissolution of the 5th parliament in 1918 and the 1919 general election. The party failed to win representation in the 1919 election.