Leo Jogiches, also known as Tyska (born 17 July 1867 in Vilnius, died 10 March 1919 in Berlin), was a Polish Jewish politician and an early socialist agitator for workers in his home, Lithuania. In 1890 he escaped prison by fleeing the country and emigrated to Switzerland where he began a long political and personal relationship with Rosa Luxemburg and they fell in love with each other.

Jogiches was a founding member of the Spartacus League, a revolutionary left-wing organisation of the German Social Democratic Party , formed at the beginning of World War I by Karl Liebknecht, Rosa Luxemburg, Franz Mehring and others. On 1 January, 1919 the League became the Communist Party of Germany. The Spartacus League led the German revolution of 1918-19, which failed, after which Luxemburg and Liebknecht were brutally murdered. Jogiches was also murdered in March 1919 while trying to investigate the assassination of Luxemburg and Karl Liebknecht.