Alfred Sohn-Rethel (4 January 1899 – 6 April 1990) was a Marxist economist and philosopher especially interested in epistemology. He also wrote about the relationship of German industry with national socialism.

Born in Neuilly-sur-Seine near Paris, Sohn-Rethel came from a family of painters and his father was a painter too. His mother came from the Oppenheim family and had influential relations with big business.

As his family did not want him also to become a painter, he was brought up by his uncle, the steel industrialist Ernst Poensgen. On Christmas 1915 he expressed a wish for a copy of Karl Marx Capital as a present. He received one and studied it intensively. Thrown out of home, he participated in the anti-war student protest in his first year at Heidelberg University in 1917.

From 1920 Sohn-Rethel was a friend of the philosopher Ernst Bloch, and he met Walter Benjamin in 1921. He came to live in Positano in 1923-4, and Naples: philosophy of the broken recorded his fascination with the relaxed Neopolitan attitude to technology. Between 1924 and 1927 he remained in Italy, "mainly in Capri, where Benjamin and Bloch were staying", meeting Adorno and Kracauer also at Capri in 1924. He stayed in contact with different members of the Frankfurt School, to whom his theoretical concerns were close. However, they never established a close working relationship because Horkheimer was afraid of social theory becoming too speculative.