Antonio Francesco Gramsci (UK: /ˈɡræmʃi/ GRAM-shee, US: /ˈɡrɑːmʃi/ GRAHM-shee; Italian: [anˈtɔːnjo franˈtʃesko ˈɡramʃi] ^ⓘ; 22 January 1891 – 27 April 1937) was an Italian Marxist philosopher and politician. 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, and remained in prison until shortly before 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 the history of Italy and Italian nationalism, the French Revolution, fascism, Taylorism and Fordism, civil society, the state, historical materialism, 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 wealth and power in capitalist societies. In Gramsci's view, the bourgeoisie develops a hegemonic culture using ideology rather than violence, economic force, or coercion. He also attempted to break from the economic determinism of orthodox 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.

Gramsci was born in Ales, in the province of Oristano, on the island of Sardinia, the fourth of seven sons of Francesco Gramsci (1860–1937) and Giuseppina Marcias (1861–1932). Francesco Gramsci was born in the small town of Gaeta, in the province of Latina, Lazio (today in the central Italian region of Lazio but at the time Gaeta was still part of Terra di Lavoro of Southern Italy), to a well-off family from the southern Italian regions of Campania and Calabria and of Arbëreshë (Italo-Albanian) descent. Gramsci himself believed that his father's family had left Albania as recently as 1821. The Albanian origin of his father's family is attested in the surname Gramsci, an Italianised form of Gramshi, which stems from the definite noun of the placename Gramsh, a small town in central-eastern Albania. Gramsci's mother belonged to a Sardinian landowning family from Sorgono, in the province of Nuoro. Francesco Gramsci worked as a low-level official, and his financial difficulties and troubles with the police forced the family to move about through several villages in Sardinia until they finally settled in Ghilarza. During his youth in Sardinia Antonio Gramsci cultivated a deep appreciation for literature and theater--reading works by Italian and European authors.

In 1898, Gramsci's father was convicted of embezzlement and imprisoned, reducing his family to destitution. The young Gramsci had to abandon schooling and work at various casual jobs until his father's release in 1904. As a boy, Gramsci suffered from health problems, particularly a malformation of the spine that stunted his growth, as his adult height was less than 5 feet, and left him seriously hunchbacked. For decades, it was reported that his condition had been due to a childhood accident—specifically, having been dropped by a nanny—but more recently it has been suggested that it was due to Pott disease, a form of tuberculosis that can cause deformity of the spine. Gramsci was also plagued by various internal disorders throughout his life.

Gramsci started secondary school in Santu Lussurgiu and completed it in Cagliari, where he lodged with his elder brother Gennaro, a former soldier whose time on the mainland had made him a militant socialist. At the time, Gramsci's sympathies did not yet lie with socialism but rather with Sardinian autonomism, as well as the grievances of impoverished Sardinian peasants and miners, whose mistreatment by the mainlanders would later deeply contribute to his intellectual growth. They perceived their neglect as a result of privileges enjoyed by the rapidly industrialising Northern Italy, and they tended to turn to a growing Sardinian nationalism, brutally repressed by troops from the Italian mainland, as a response.

In 1911, Gramsci won a scholarship to study at the University of Turin, sitting the exam at the same time as Palmiro Togliatti. At Turin, he read literature and took a keen interest in linguistics, which he studied under Matteo Bartoli. Gramsci was in Turin while it was going through industrialization, with the Fiat and Lancia factories recruiting workers from poorer regions. Trade unions became established, and the first industrial social conflicts started to emerge. Gramsci frequented socialist circles as well as associating with Sardinian emigrants on the Italian mainland. Both his earlier experiences in Sardinia and his environment on the mainland shaped his worldview. Gramsci joined the Italian Socialist Party (PSI) in late 1913, where he would later occupy a key position and observe from Turin the Russian Revolution.

Although showing a talent for his studies, Gramsci had financial problems and poor health. Together with his growing political commitment, these led to him abandoning his education in early 1915, at age 24. By this time he had acquired an extensive knowledge of history and philosophy. At university, he had come into contact with the thought of Antonio Labriola, Rodolfo Mondolfo, Giovanni Gentile, and most importantly, Benedetto Croce, possibly the most widely respected Italian intellectual of his day. Labriola especially propounded a brand of Hegelian Marxism that he labelled "philosophy of praxis". Although Gramsci later used this phrase to escape the prison censors, his relationship with this current of thought was ambiguous throughout his life.