This paper presents a dynamic perspective in which the psychological contract is treated as a structured set of beliefs that are held by individual employees about the mutual obligations of the organization as employer and themselves as employees. This set of beliefs is assumed to produce a state of commitment to the organization in which the employee is willing to accept work roles and tasks offered by the organization, and to carry them out in accordance with certain standards. The dynamic model that is presented can help to explain why the commitment of employees remains relatively stable over time, and why it may suddenly decrease or increase under circumstances that are perceived as critical by the employee. The model assumes that the employee's evaluation of the organization's behavior changes over time, but that the structure of the psychological contract and the associated commitment change only when certain limits are overstepped. This perspective on changes in the psychological contract transforms the concept into a powerful construct that may lead to fruitful research on the dynamics of organization-employee relationships. Implications for future research are discussed.