Capital. Critique of Political Economy (German: Das Kapital. Kritik der politischen Ökonomie, pronounced [das kapiˈtaːl, kʁiːtɪk deːɐ pɔliːtɪʃən øːkoːnoːmiː]; 1867–1883) by Karl Marx is a foundational theoretical text in materialist philosophy, economics and politics. Marx aimed to reveal the economic patterns underpinning the capitalist mode of production, in contrast to classical political economists such as Adam Smith, Jean-Baptiste Say, David Ricardo and John Stuart Mill.

Marx did not live to publish the planned second and third parts, but they were both completed from his notes and published after his death by his colleague Friedrich Engels.