Institutions are socially constructed frameworks composed of conventions that prescribe behavior, cognition, and communication in given contexts. Institutions are maintained or changed by people who act and interact with each other. Examples of institutions include long-established organizations such as universities or hospitals but also include widespread practices such as marriage or voting and ways of working and interacting, such as markets, governments, and the professions. Institutions are important to organizations because they become taken for granted, transcend and penetrate particular organizations, and are constituted by normative systems and cognitive understandings that give enduring meaning to social exchange, thus enabling a self-reproducing social order. Thus, institutions may be thought of as the foundations of organizations. This entry explores the history of the institutional approach to organizational communication, the communicative nature of institutions, and the key concepts used in institutional theory and analysis. The process of institutionalization is also discussed.