Social Democratic Workers' Party in Subcarpathian Rus'

The Social Democratic Workers' Party in Subcarpathian Rus' (Ukrainian: Соціал-демократична робітнича партія на Підкарпатській Русі, Sotsial-demokratichna robitnicha partiya na Pidkarpats'kiy Rusi; Czech: Sociálně demokratická strana dělnická na Podkarpatské Rusi) was a social democratic political party in Carpathian Ruthenia (or Subcarpathian Rus') in Czechoslovakia. The party was founded in 1919. At the party congress in September 1922 the party adopted a party programme which acknowledged the inclusion of Carpathian Ruthenia as an autonomous region in the Czechoslovak Republic. The party obtained the support of the Gregory Žatkovich, the first governor of Subcarpathian Rus, during his tenure 1920–1921.

The main difference between the party and the Czechoslovak Social Democratic Workers Party (ČSDSD) was that ČSDSD supported the government in Prague, whilst the Subcarpathian party opposed it as the government did not support the formation of an autonomous region of all Rusyn-inhabited areas.