Wage slavery or slave wages refers to a person's dependence on wages (or a salary) for their livelihood, especially when wages are low, treatment and conditions are poor, and there are few chances of upward mobility.

The term is often used by critics of wage-based employment to criticize the exploitation of labor and social stratification, with the former seen primarily as unequal bargaining power between labor and capital, particularly when workers are paid comparatively low wages, such as in sweatshops, and the latter is described as a lack of workers' self-management, fulfilling job choices and leisure in an economy. The criticism of social stratification covers a wider range of employment choices bound by the pressures of a hierarchical society to perform otherwise unfulfilling work that deprives humans of their "species character" not only under threat of extreme poverty and starvation, but also of social stigma and status diminution. Historically, many socialist organisations and activists have espoused workers' self-management or worker cooperatives as possible alternatives to wage labor.

Similarities between wage labor and slavery were noted as early as Cicero in Ancient Rome, such as in De Officiis. With the advent of the Industrial Revolution, thinkers such as Pierre-Joseph Proudhon and Karl Marx elaborated the comparison between wage labor and slavery, and engaged in critique of work while Luddites emphasized the dehumanization brought about by machines. The introduction of wage labor in 18th-century Britain was met with resistance, giving rise to the principles of syndicalism and anarchism.

Before the American Civil War, Southern defenders of keeping African Americans in slavery invoked the concept of wage slavery to favourably compare the condition of their slaves to workers in the North. The United States abolished most forms of slavery after the Civil War, but labor union activists found the metaphor useful – according to historian Lawrence Glickman, in the Gilded Age "[r]eferences abounded in the labor press, and it is hard to find a speech by a labor leader without the phrase".