Cuba has had a socialist political system since 1959 based on the "one state – one party" principle. Cuba is constitutionally defined as a Marxist–Leninist state. The present Constitution of Cuba, which was passed in a 2019 referendum, also describes the role of the Communist Party of Cuba to be the "leading force of society and of the state" and as having the capability of setting national policy, and First Secretary of the Communist Party is the most powerful position in Cuba. The 2019 Constitution of Cuba identifies the ideals represented by Cuban independence hero José Martí and revolutionary leader Fidel Castro as the primary foundation of Cuba's political system, while also stressing the importance of the influence of the ideas of Marx, Engels, and Lenin.

The President of Cuba is Miguel Díaz-Canel, who succeeded Raúl Castro as First Secretary of the Communist Party of Cuba in 2021. Díaz-Canel is the first ruler of Communist Cuba to not hail from the family of Fidel or Raúl Castro. Executive power is exercised by the government, which is represented by the Council of Ministers, headed by the Prime Minister of Cuba. Legislative power is exercised through the unicameral National Assembly of People's Power, which is constituted as the maximum authority of the state. With effect from 10 October 2019, Miguel Díaz-Canel is the president and Manuel Marrero is the Prime Minister of Cuba. The previous president of the State Council was Raúl Castro, brother of former leader Fidel Castro; Raúl Castro remained First Secretary of the Communist Party of Cuba, and Commander-in-Chief of the Revolutionary Armed Forces until 19 April 2021. Fidel Castro ruled from 1959 to 2006, before illness forced him to hand power to his brother. Esteban Lazo Hernández is the president of the National Assembly.

Political scientists characterize the political system of Cuba as a single-party authoritarian regime where political opposition is not permitted. There are elections in Cuba, but they are not considered democratic. Censorship of information (including limits to internet access) is extensive, and independent journalism is repressed in Cuba; Reporters Without Borders has characterized Cuba as one of the worst countries in the world for press freedom.