Talcott Parsons (born Dec. 13, 1902, Colorado Springs, Colorado, U.S.—died May 8, 1979, Munich, West Germany) was an American sociologist and scholar whose theory of social action influenced the intellectual bases of several disciplines of modern sociology. His work is concerned with a general theoretical system for the analysis of society rather than with narrower empirical studies. He is credited with having introduced the work of Max Weber and Vilfredo Pareto to American sociology.

After receiving his B.A. from Amherst College in 1924, Parsons studied at the London School of Economics and at the University of Heidelberg, where he received his Ph.D. in 1927. He joined the faculty of Harvard University as an instructor in economics and began teaching sociology in 1931. In 1944 he became a full professor, and in 1946 he was appointed chairman of the new department of social relations, a post Parsons held until 1956. He remained at Harvard until his retirement in 1973. Parsons also served as president of the American Sociological Society in 1949.

Parsons united clinical psychology and social anthropology with sociology, a fusion still operating in the social sciences. His work is generally thought to constitute an entire school of social thought. In his first major book, The Structure of Social Action (1937), Parsons drew on elements from the works of several European scholars (Weber, Pareto, Alfred Marshall, and Émile Durkheim) to develop a common systematic theory of social action based on a voluntaristic principle—i.e., the choices between alternative values and actions must be at least partially free. Parsons defined the locus of sociological theory as residing not in the internal field of personality, as postulated by Sigmund Freud and Weber, but in the external field of the institutional structures developed by society. In The Social System (1951), he turned his analysis to large-scale systems and the problems of social order, integration, and equilibrium. He advocated a structural-functional analysis, a study of the ways in which the interrelated and interacting units that form the structures of a social system contribute to the development and maintenance of that system.

Other works by Parsons include Essays in Sociological Theory (1949; rev. ed. 1954), Economy and Society (1956; with Neil J. Smelser), Structure and Process in Modern Societies (1960), Societies: Evolutionary and Comparative Perspectives (1966), Sociological Theory and Modern Society (1967), Politics and Social Structure (1969), and The American University (1973; with Gerald M. Platt and Neil J. Smelser).