Cuba is governed under a constitution adopted in 1976, as subsequently amended. It defines the country as a socialist state in which all power belongs to the working people. The Communist Party is Cuba's only legal political party.

The central legislature of Cuba is the National Assembly of People's Power, whose 510 members are elected to five-year terms by direct universal voting. The National Assembly, which regularly meets twice during the year, elects a Council of State of about 30 members to carry out its functions when it is not in session. The Council of State includes a president, who is the country's head of state; a first vice president; and five other vice presidents. The National Assembly also chooses a Council of Ministers, which is Cuba's chief administrative body. The council is headed by the president.

Cuba is divided into 169 municipalities and 14 provinces; the Isla de la Juventud municipality is not part of any province, and its affairs are overseen directly by the central government. Each municipality has an assembly composed of delegates elected to terms of two and one-half years. The municipal assemblies choose executive committees, the members of which make up five regional assemblies for each province. These regional bodies also have executive committees, which together form the membership of the provincial assembly (in turn, headed by an executive committee). At each level the executive committee oversees the day-to-day administrative functions of its assembly.

Judicial power is exercised by the People's Supreme Court on the national level, by courts of justice in cases that are provincial or regional in nature, and by the municipal courts. Revolutionary tribunals are convened to deal with crimes against the state.