Forst may refer to:

Rosa Luxemburg (Rosalia Luxemburg, Polish: Róża Luksemburg; 5 March 1871,Zamość, Vistula Land, Russia – 15 January 1919, Berlin, Germany) was a Marxist theorist, philosopher, economist and revolutionary socialist of Polish Jewish descent who became a naturalized German citizen. She was successively a member of the Social Democracy of the Kingdom of Poland and Lithuania (SDKPiL), the Social Democratic Party of Germany (SPD), the Independent Social Democratic Party (USPD), and the Communist Party of Germany (KPD).

In 1915, after the SPD supported German involvement in World War I, she and Karl Liebknecht co-founded the anti-war Spartakusbund (Spartacist League) which eventually became the Communist Party of Germany (KPD). During the German Revolution she founded the Die Rote Fahne (The Red Flag), the central organ of the Spartacist movement.

She regarded the Spartacist uprising as a blunder, but supported it after Liebknecht ordered it without her knowledge. When the revolt was crushed by the social democrat government and the Freikorps (World War I veterans who banded together into right-wing paramilitary groups), Luxemburg, Liebknecht and some of their supporters were captured and murdered. Luxemburg was shot and her body thrown in the Landwehr Canal in Berlin. After their deaths, Luxemburg and Karl Liebknecht became martyrs for Marxists. According to the Federal Office for the Protection of the Constitution, commemoration of Rosa Luxemburg and Karl Liebknecht continues to play an important role among the German far-left.