The idea that socialism is a transitional stage leading to communism is a central concept in Marxist theory. Karl Marx and Friedrich Engels, the founders of Marxism, introduced this concept in their writings. They believed that socialism, characterized by the collective ownership of the means of production and the abolition of class distinctions, would ultimately pave the way for a classless society, which they referred to as communism.

Marx and Engels articulated their views in various works, including "The Communist Manifesto" (1848) and "Critique of the Gotha Program" (1875). According to their theory, socialism would be a necessary step toward achieving the ultimate goal of communism, where there would be no private property, no class divisions, and a society organized on the principle of "from each according to their ability, to each according to their needs."