• 
  State ownership, where the government owns all means of production


• 
  Cooperative ownership, which might take the form of a employee stock ownership plan in a market economy, a worker's cooperative (where employees own and self-manage the organization), consumers' co-operative, housing cooperative (owned by the residents), etc.


• 
  Common ownership, where the entire society shares things


• 
  Citizen ownership of equity, where the government or employee pension organizations own the stock of corporations in a market socialist economy

Varieties of socialism can be categorized in a variety of ways:

• 
  Reformism versus revolutionary socialism – whether a socialist economy should be obtained through changes made by existing governmental systems or whether a revolution should overthrow the existing government


• 
  State socialism versus libertarian socialism – whether economic control and ownership should be centralized (such as with a command economy or state capitalism where government-owned corporations dominate a market economy) or decentralized among small collectively owned organizations or industrial guilds


• 
  Democratic socialism (advocating worker's self-management and workplace democracy within a market socialist, participatory or decentralized planned economy) versus authoritarian socialism as seen in Marxist-Leninist countries such as the Soviet Union
  


• 
  Market socialism vs. non-market socialism – whether goods, services, and factors of production can be traded in a market using currency and prices
  

Non-market socialism involves the substitution of factor markets and money with engineering and technical criteria based on calculation performed in-kind, thereby producing an economic mechanism that functions according to different economic laws from those of capitalism. Non-market socialism aims to circumvent the inefficiencies and crises traditionally associated with capital accumulation and the profit system. By contrast, market socialism retains the use of monetary prices, factor markets and in some cases the profit motive, with respect to the operation of socially owned enterprises and the allocation of capital goods between them. Profits generated by these firms would be controlled directly by the workforce of each firm, or accrue to society at large in the form of a social dividend. The socialist calculation debate discusses the feasibility and methods of resource allocation for a socialist system.

Socialist politics has been both internationalist and nationalist in orientation; organised through political parties and opposed to party politics; at times overlapping with trade unions, and at other times independent and critical of unions; and present in both industrialised and developing countries. Originating within the socialist movement, social democracy has embraced a mixed economy with a market that includes substantial state intervention in the form of income redistribution, regulation, and a welfare state. Economic democracy proposes a sort of market socialism where there is more decentralized control of companies, currencies, investments, natural resources.

The socialist political movement includes a set of political philosophies that originated in the revolutionary movements of the mid-to-late 18th century and out of concern for the social problems that were associated with capitalism. By the late 19th century, after the work of Karl Marx and his collaborator Friedrich Engels, socialism had come to signify opposition to capitalism and advocacy for a post-capitalist system based on some form of social ownership of the means of production. By the 1920s, social democracy and communism had become the two dominant political tendencies within the international socialist movement. By this time, socialism emerged as "the most influential secular movement of the twentieth century, worldwide. It is a political ideology (or world view), a wide and divided political movement" and while the emergence of the Soviet Union as the world's first nominally socialist state led to socialism's widespread association with the Soviet economic model, some economists and intellectuals argued that in practice the model functioned as a form of state capitalism or a non-planned administrative or command economy. Socialist parties and ideas remain a political force with varying degrees of power and influence on all continents, heading national governments in many countries around the world. Today, some socialists have also adopted the causes of other social movements, such as environmentalism, feminism and progressivism.