The Socialist Party of Pennsylvania was a socialist political party in the U.S. state of Pennsylvania. It was founded in 1901 in Reading, Pennsylvania and received a state charter from the Socialist Party of America the following year. Reading was one of three cities which found considerable electoral success. Readings Socialists elected multiple state legislators, city councilors as well as mayor J. Henry Stump. The Socialist Party of America nominated former Pennsylvania Representative and SPA member Darlington Hoopes for President in 1952 and 1956. In 1965, the Reading chapter of the party was down to approximately 25 members. The national party was renamed Social Democrats, USA in 1972.
A successor organization, the Socialist Party USA, was formed in 1973 by the Debs caucus of the old SPA, a group which still supported independent socialist political action. As of 2016 the SPUSA has one local in the state, located in Philadelphia.