The Frankfurt School (German: Frankfurter Schule) refers to a school of neo-Marxist interdisciplinary social theory, particularly associated with the Institute for Social Research at the University of Frankfurt am Main. The school initially consisted of dissident Marxists who believed that some of Marx's followers had come to parrot a narrow selection of Marx's ideas, usually in defense of orthodox Communist parties. Meanwhile, many of these theorists experienced that traditional Marxist theory could not adequately explain the turbulent and unexpected development of capitalist societies in the twentieth century. Critical of both capitalism and Soviet socialism, their writings pointed to the possibility of an alternative path to social development.

Although sometimes only loosely affiliated, Frankfurt School theorists spoke with a common paradigm in mind, thus sharing the same assumptions and being preoccupied with similar questions. In order to fill in the perceived omissions of traditional Marxism, they sought to draw answers from other schools of thought, hence using the insights of antipositivist sociology, psychoanalysis, existential philosophy, and other disciplines. The school's main figures sought to learn from and synthesize the works of such varied thinkers as Kant, Hegel, Marx, Freud, Weber and Lukács.