"Theses on Feuerbach" (in German: "Thesen über Feuerbach") are eleven short philosophical notes written by Karl Marx (likely in 1845). They articulate Marx’s critique of the ideas of his fellow Young Hegelian philosopher, Ludwig Feuerbach. However, the text is often seen as more ambitious, critiquing the contemplative materialism of the Young Hegelians alongside all forms of philosophical idealism.

The "Theses" identify practical action (both material and theoretical) as the only true form of philosophy, concluding with the famous line: “The philosophers have only interpreted the world, in various ways; the point, however, is to change it.” (In German: “*Die Philosophen haben die Welt nur verschieden interpretiert; es kömmt drauf an, sie zu verändern*”). While the text retains the critical stance of German idealism, it reinterprets critique in practical, material, and political terms, directly leading to Marx’s later assertion that the "critique of arms" must, at some point, work for the "arms of critique."

Marx did not publish *Theses on Feuerbach* during his lifetime; they were later edited by Friedrich Engels and published in 1888 alongside his book *Ludwig Feuerbach and the End of Classical German Philosophy*, with the original text appearing in 1924 and again in 1932 through the Moscow Institute of Marxism-Leninism within *The German Ideology*. The writings essentially served as notes for Marx to organize other works on the principles he intended to develop, functioning as a reminder to himself—a draft forming the foundation for future concepts he was yet to establish.