Leon "Leo" Jogiches (German: Leo Jogiches; Russian: ??? "???" ???????; 17 July 1867 – 10 March 1919), also commonly known by the party name Jan Tyszka, was a Marxist revolutionary active in Poland, Lithuania and Germany.
Jogiches was a founder of the political party known as The Social Democracy of the Kingdom of Poland (main forerunner of the Communist Party of Poland) in 1893 and a key figure in the underground Spartacus League in Germany (main forerunner of the Communist Party of Germany) during the years of World War I.
For many years the personal companion and a close political ally of internationally famous revolutionary Rosa Luxemburg, Jogiches was assassinated in Berlin by right-wing paramilitary forces in March 1919 while investigating Luxemburg's murder some weeks before.