Enrico Berlinguer (Italian: [enˈriːko berliŋˈɡwɛr] (listen); 25 May 1922 – 11 June 1984) was an Italian politician, considered the most popular leader of the Italian Communist Party (PCI), which he led as the national secretary from 1972 until his death during a tense period in Italy's history, marked by the Years of Lead and social conflicts, such as the Hot Autumn of 1969–1970.

During his leadership, he distanced the party from the influence of the Communist Party of the Soviet Union and pursued a moderate line, repositioning the party within Italian politics and advocating accommodation and national unity. This strategy came to be termed Eurocommunism, and he was seen as its main spokesperson. It came to be adopted by Western Europe's other significant like-minded parties, such as the Communist Party of Spain and later the French Communist Party; its significance as a political force was cemented by a 1977 meeting in Madrid between Berlinguer, Georges Marchais, and Santiago Carrillo. Berlinguer described his alternative model of socialism, distinct from both the Soviet bloc and the capitalism practiced by Western countries during the Cold War, as terza via; his usage of the term has no relation to the more centrist Third Way practiced by subsequent Prime Ministers Romano Prodi and Matteo Renzi.

Under Berlinguer, the PCI reached the height of its success, winning significant victories in the country's regional and local elections in 1975, and 34% of the vote in the 1976 Italian general election, its highest share of the vote and number of seats. With these gains, he negotiated the Historic Compromise with Christian Democracy (DC), lending support to their government in exchange for consultation on policy decisions, as well as social reforms. He took a firm stand against terrorism after the kidnapping and murder of Aldo Moro, and used the PCI's influence to steer Italian labour unions towards moderating wage demands to cope with the country's severe inflation rate after the 1973 oil crisis. These stands were not reciprocated with sufficient concessions from Giulio Andreotti's government, leading the PCI to leave the coalition in 1979. The combination of austerity advocacy, hard line against the Red Brigades, and attempts at an accommodation with the DC affected the PCI's vote at the 1979 Italian general election and the compromise was ultimately ended in 1980. The PCI remained in national opposition for the rest of Berlinguer's tenure, retaining a solid core of support at the 1983 Italian general election; its main strength from that point would remain at the regional and local level.

Berlinguer had an austere and modest but charismatic personality, and despite the difficulties that confronted the PCI during the Historic Compromise, he remained a popular politician, respected for his principles, conviction, and bold stands. He characterised the PCI as an honest party in Italy's corruption-ravaged politics, an image that preserved the party's reputation during the Mani pulite corruption scandals. He was characterised by Patrick McCarthy as "the last great communist leader in Western Europe", and remains identified with the causes of Eurocommunism, opposition to Soviet repression in Eastern Europe, and democratic change in Italy.