Antonio Francesco Gramsci (UK: GRAM-shee, US: GRAHM-shee, Italian: [anˈtɔːnjo franˈtʃesko ˈɡramʃi] (listen); 22 January 1891 – 27 April 1937) was an Italian Marxist philosopher, journalist, linguist, writer, and politician. He wrote on philosophy, political theory, sociology, history, and linguistics. He was a founding member and one-time leader of the Italian Communist Party. A vocal critic of Benito Mussolini and fascism, he was imprisoned in 1926 where he remained until his death in 1937.

During his imprisonment, Gramsci wrote more than 30 notebooks and 3,000 pages of history and analysis. His Prison Notebooks are considered a highly original contribution to 20th-century political theory. Gramsci drew insights from varying sources – not only other Marxists but also thinkers such as Niccolò Machiavelli, Vilfredo Pareto, Georges Sorel, and Benedetto Croce. The notebooks cover a wide range of topics, including Italian history and nationalism, the French Revolution, fascism, Taylorism and Fordism, civil society, folklore, religion, and high and popular culture.

Gramsci is best known for his theory of cultural hegemony, which describes how the state and ruling capitalist class – the bourgeoisie – use cultural institutions to maintain power in capitalist societies. The bourgeoisie, in Gramsci's view, develops a hegemonic culture using ideology, rather than violence, economic force, or coercion. Hegemonic culture propagates its own values and norms so that they become the "common sense" values of all and thus maintain the status quo. Cultural hegemony is therefore used to maintain consent to the capitalist order, rather than the use of force to maintain order. This cultural hegemony is produced and reproduced by the dominant class through the institutions that form the superstructure.

Gramsci also attempted to break from the economic determinism of traditional Marxist thought, and so is sometimes described as a neo-Marxist. He held a humanistic understanding of Marxism, seeing it as a "philosophy of praxis" and an "absolute historicism" that transcends traditional materialism and traditional idealism.