Some of the world's most powerful corporations practise what Shoshana Zuboff (2015; 2019) calls ‘surveillance capitalism’. The core of their business is harvesting, analysing and selling data about the people who use their products. In Zuboff's view, the first corporation to engage in surveillance capitalism was Google, followed by Facebook; recently, firms such as Microsoft and Amazon have pivoted towards such a model. In this paper, I suggest that Karl Marx's analysis of the relations between industrial capitalists and workers is closely analogous to the relations between surveillance capitalists and users. Furthermore, three problematic aspects of industrial capitalism that Marx describes – alienation, exploitation and accumulation – are also aspects, in new forms, of surveillance capitalism. I draw heavily on Zuboff's work to make these parallels. However, my Marx-inspired account of surveillance capitalism differs from hers over the nature of the exchange between users and surveillance capitalists. For Zuboff, this is akin either to robbery or the gathering of raw materials; on the Marx-inspired account it is a voluntary sale. This difference has important implications for the question of how to resist surveillance capitalism.