Silesian Parliament or Silesian Sejm (Polish: Sejm Śląski, German: Schlesisches Parlament, Czech: Slezský parlament) was the governing body of the Silesian Voivodeship (1920–1939), an autonomous voivodeship of the Second Polish Republic between 1920 and 1945. It was elected in democratic elections and had certain influence over the usage of taxes collected in Silesia. It consisted of 48 deputies (24 from 1935).
The eastern part of Upper Silesia became part of the Second Polish Republic following the Silesian Uprisings throughout the Upper Silesian region between 1918 and 1921, and Upper Silesia Plebiscite. The land was subsequently divided by an allied commission and the League of Nations, leaving Katowice region on the Polish side. Together with Cieszyn Silesia it formed Silesian Voievodeship with significant autonomy (Silesian Parliament as a constituency and Silesian Voivodship Council as the executive body).
Designed by architect Lech Wojtyczko, the Silesian Parliament was built in 1925-1929. For a very long time it was the biggest structure in Poland. Currently it hosts the offices of the Silesian Voivodship. The building has seven floors and contains one of four paternosters currently in use in Poland. The Polish architect Adolf Szysko-Bohusz announced a competition for the design of the new Silesian Parliament in 1925, who wished the building to espouse the local Polish cultural identity of the region, instead of the more customary German/ Prussian style. When the building was inaugurated in May 1929, Michal Grazynski, President of the Province of Upper silesia, called the building a "material symbol of Polish culture and power".