Socjalizm (łac. societas – wspólnota) – wieloznaczne pojęcie, odnoszące się do ideologii politycznej wywodzącej się z utopijnej filozofii politycznej rozwijanej w latach 30. i 40. XIX wieku we Francji lub doktryna gospodarcza postulująca upowszechnienia świadczeń socjalnych i poddania gospodarki kontroli społecznej (poprzez instytucje państwowe, samorządowe, korporacyjne lub spółdzielcze). Częścią wspólną wszystkich odmian socjalizmu jest (częściowe lub całkowite) odrzucenie idei kapitalizmu oraz promowanie idei sprawiedliwości społecznej.

Socjalizm wywodzi się od filozofii rozwijanej na przełomie XVIII i XIX wieku przez działaczy tj. Henri de Saint-Simon, Pierre Leroux, Charles Fourier) i Robert Owen. Celem ówczesnych socjalistów było zbudowanie społeczeństwa bez ubóstwa, gdzie siły rynkowe nie są głównym mechanizmem podziału bogactwa oraz w którym funkcjonowanie społeczeństwa opiera się na wspólnej własności, wzajemnej współpracy i altruizmie. Teoretykami socjalizmu połowy XIX w. byli: Karol Marks, Fryderyk Engels, Pierre Proudhon i Michał Bakunin twórcy marksizmu, anarchizmu i anarchokolektywizmu. Wkrótce na gruncie marksistowskiej wersji socjalizmu powstała ideologia komunistyczna oraz ideologia socjaldemokratyczna. Elementy ideologii socjalistycznej były także łączone z nacjonalizmem, chrześcijaństwem, islamem etc.

Socialism is a social and economic system characterised by social ownership of the means of production and co-operative management of the economy,[1][2] as well as a political theory and movement that aims at the establishment of such a system.[3][4] "Social ownership" may refer to cooperative enterprises, common ownership, state ownership, citizen ownership of equity, or any combination of these.[5] There are many varieties of socialism and there is no single definition encapsulating all of them.[6] They differ in the type of social ownership they advocate, the degree to which they rely on markets or planning, how management is to be organised within productive institutions, and the role of the state in constructing socialism.[7]

A socialist economic system is based on the organisational precept of production for use, meaning the production of goods and services to directly satisfy economic demand and human needs where objects are valued based on their use-value or utility, as opposed to being structured upon the accumulation of capital and production for profit.[8] In the traditional conception of a socialist economy, coordination, accounting and valuation would be performed in kind (using physical quantities), by a common physical magnitude, or by a direct measure of labour-time in place of financial calculation.[9][10] Distribution of output is based on the principle of to each according to his contribution. The exact methods of resource allocation and valuation are the subject of debate within the broader socialist calculation debate.

In the Marxist theory of historical materialism, it is predicted that further advances in technology and the productive forces will give rise to a more advanced stage of development referred to as communism, a society in which classes and the state are no longer present, and there is access abundance to final goods, and thus distribution is based on to each according to his need.

The socialist political movement includes a diverse array of political philosophies. Core dichotomies within the socialist movement include the distinction between reformism and revolutionary socialism and between state socialism and libertarian socialism. State socialism calls for the nationalisation of the means of production as a strategy for implementing socialism, while libertarian socialism opposes the use of state power – whether exercised through parliamentary politics or state-owned industry – as a means to achieve socialism.[11] Democratic socialism highlights the central role of democratic processes and political systems and is usually contrasted with non-democratic political movements that advocate socialism.

Modern socialism originated from an 18th-century intellectual and working class political movement that criticised the effects of industrialisation and private property on society. The revival of republicanism in the American Revolution of 1776 and the egalitarian values introduced by the French Revolution of 1789 gave rise to socialism as a distinct political movement. In the early 19th-century, "socialism" referred to any concern for the social problems of capitalism irrespective of the solutions to those problems. However, by the late 19th-century, "socialism" had come to signify opposition to capitalism and advocacy for an alternative post-capitalist system based on some form of social ownership.[12] During this time, German philosopher Karl Marx and his collaborator Friedrich Engels published works criticizing the utopian aspects of contemporary socialist trends and applied a materialist understanding of socialism as a phase of development which will come about through social revolution instigated by escalating and conflicting class relationships within capitalism.[13] The socialist movement came to be the most influential worldwide movement and worldview of the twentieth century.[14]