István Mészáros (born 19 December 1930) is a Hungarian Marxist philosopher, and Professor Emeritus at the University of Sussex. He held the Chair of Philosophy at Sussex for fifteen years and was earlier Professor of Philosophy and Social Science for four years at York University.
He can be linked to the so-called Budapest School, a group of Hungarian philosophers who were taught or influenced by Georg Lukács, including Ágnes Heller and György Márkus. He left his native Hungary in 1956 after the Soviet invasion and worked for a time in Turin, Italy, before settling in the UK. He is the author of numerous books.