Communism is a philosophical, social, political, and economic ideology and movement whose goal is the establishment of a communist society, namely a socioeconomic order structured upon the ideas of common ownership of the means of production and the absence of social classes, money, and the state. Communism is a specific, yet distinct, form of socialism. Communists agree on the withering away of the state but disagree on the means to this end, reflecting a distinction between a more libertarian approach of communization, revolutionary spontaneity, and workers' self-management, and a more vanguardist or Communist party-driven approach through the development of a constitutional socialist state

Variants of communism have been developed throughout history, including anarcho-communism and Marxist schools of thought. Communism includes a variety of schools of thought which broadly include Marxism, Leninism, and libertarian communism as well as the political ideologies grouped around both, all of which share the analysis that the current order of society stems from capitalism, its economic system and mode of production, namely that in this system there are two major social classes, the relationship between these two classes is exploitative, and that this situation can only ultimately be resolved through a social revolution. The two classes are the proletariat (the working class), who make up the majority of the population within society and must work to survive, and the bourgeoisie (the capitalist class), a small minority who derives profit from employing the working class through private ownership of the means of production. According to this analysis, revolution would put the working class in power and in turn establish social ownership of the means of production which is the primary element in the transformation of society towards a communist mode of production.

In the 20th century, Communist governments espousing Marxism–Leninism and its variants came into power in parts of the world, first in the Soviet Union with the Russian Revolution of 1917, and then in portions of Eastern Europe, Asia, and a few other regions after World War II. Along with social democracy, communism became the dominant political tendency within the international socialist movement by the 1920s. Criticism of communism can be divided into two broad categories, namely that which concerns itself with the practical aspects of 20th century Communist states and that which concerns itself with communist principles and theory. Several academics and economists, among other scholars, posit that the Soviet model under which these nominally Communist states in practice operated was not an actual communist economic model in accordance with most accepted definitions of communism as an economic theory but in fact a form of state capitalism, or non-planned administrative-command system.