Conceptualizing stress as an interaction of organizational or work characteristics (stress stimuli) and individual characteristics (stress resistance), this paper reports a study of teacher stress in 42 elementary school organizations and 45 secondary school organizations. Organizational stress is operationalized as the aggregate average response to a self-report inventory on the teachers' psychological and physiological states on the job. This analysis does not address the variance within an organization predicted by individual job characteristics and personality characteristics, but analyzes stress using organizational scores, emphasizing the shared variance in stress within organizations. Differences emerged between predictors of psychological and physiological stress and between predictors of stress for elementary and secondary teachers. Among significant independent variables were rationality of promotion process, student/teacher ratio, decisional deprivation, role ambiguity, teaching support ratio, supervisory behavior, and routinization. The importance of this type of analysis is concluded to lie in its implications for alleviating stress by altering organizational structures and work processes. (MJL)