Maoism, also known as Mao Zedong Thought, is a variety of Marxism–Leninism that Mao Zedong developed while trying to realize a socialist revolution in the agricultural, pre-industrial society of the Republic of China and later the People's Republic of China. A difference between Maoism and traditional Marxism–Leninism is that a united front of progressive forces in class society would lead the revolutionary vanguard in pre-industrial societies rather than communist revolutionaries alone. This theory, in which revolutionary praxis is primary and ideological orthodoxy is secondary, represents urban Marxism–Leninism adapted to pre-industrial China. Later theoreticians expanded on the idea that Mao had adapted Marxism–Leninism to Chinese conditions, arguing that he had in fact updated it fundamentally and that Maoism could be applied universally throughout the world. This ideology is often referred to as Marxism–Leninism–Maoism to distinguish it from the original ideas of Mao.

Marxism–Leninism is a communist ideology that became the largest faction of the communist movement in the world in the years following the October Revolution. It was the predominant ideology of most communist governments throughout the 20th century. It was developed in Russia by Joseph Stalin and drew on elements of Bolshevism, orthodox Marxism, and Leninism. It was the state ideology of the Soviet Union, Soviet satellite states in the Eastern Bloc, and various countries in the Non-Aligned Movement and Third World during the Cold War, as well as the Communist International after Bolshevization.