Rudolf Hilferding (10 August 1877 – 11 February 1941) was an Austrian-born Marxist economist, leading socialist theorist, politician and chief theoretician for the Social Democratic Party of Germany (SPD) during the Weimar Republic. He is almost universally recognized as the SPD's foremost theoretician of his century, and a physician.

He was born in Vienna, where he received a doctorate having studied medicine. After becoming a leading journalist for the SPD, he participated in the November Revolution in Germany and was Finance Minister of Germany in 1923 and from 1928 to 1929. In 1933 he fled into exile, living in Zurich and then Paris, where he died in custody of the Gestapo in 1941.

Hilferding was a proponent of the "economic" reading of Karl Marx identifying with the "Austro-Marxian" group. He was the first to put forward the theory of organized capitalism. He was the main defender of Marxism from critiques by Austrian School economist and fellow Vienna resident Eugen Boehm von Bawerk. Hilferding also participated in the "Crises Debate" – disputing Marx's theory of the instability and eventual breakdown of capitalism on the basis that the concentration of capital is actually stabilizing. He edited leading publications such as Vorwärts, Die Freiheit, and Die Gesellschaft. His most famous work was Das Finanzkapital (Finance capital), one of the most influential and original contributions to Marxist economics with substantial influence on Marxist writers such as Vladimir Lenin and Nikolai Bukharin influencing his writings on imperialism.