The Jewish Social Democratic Party (in Yiddish, Yidishe sotsial-demokratishe partey, Polish: Żydowska Partia Socjal-Demokratyczna, abbreviated ŻPS) was a political party in Galicia and later also Bukovina, established in a split from the Polish Social Democratic Party of Galicia (PPSD) in 1905. The party made its first public appearance on May 1, 1905, with separate May Day rallies in Kraków, Lemberg, Tarnów and Przemyśl. However, as the new party stressed that it was not a competitor of the existing Social Democratic parties, they later joined the PPSD celebrations.
The Party, often nicknamed the 'Galician Bund', was influenced by the Bund in Russia and was opposed to Zionism.
ŻPS held its founding congress in June 1905. The second congress was held in 1906.
Its founding theoretician and secretary was Henryk Grossman. While the Party sought affiliation to the Social Democratic Workers Party of Austria, this was refused. The ŻPS became the largest organisation of Jewish workers in Galicia.
In the initial period of the existence of the party, it publish a monthtly titled Der yudisher sotsial-demokrat. In October 1905 it was replaced by a weekly, Der sotsial-demokrat. As of 1910, Der sotsial-demokrat had a circulation of 2000.
In 1911 the Jewish Social Democracy in Galicia, the Jewish affiliate section of the PPSD, merged into the ŻPS. The Jewish Social Democracy in Galicia had 377 members at the time of the merger. The strength of the party reached its peak when the Bukovina Bundists merged into the party the following year. The united party took the name Jewish Social Democratic Party in Galicia and Bukovina.