The crowding model suggests that high density alone does not lead to the development of stress reactions. In any setting, occupants must manage their environment to achieve their goals. When environments become crowded goal attainment may be thwarted, and individuals attempt to cope with these barriers using behaviors such as (1) developing alternative goal paths and (2) cooperating with others to attain goals. If these alternative behaviors are unsuccessful, the individual may feel a lack of environmental control. If the individual cannot escape this environment, stress develops. Several factors affect this process, including perceptions of the threat to goal attainment, the goal structure of the group occupying the environment, and (3) the range of resources available to the individual for coping. Research on crowding in laboratory and residential settings has indicated that a lack of group cooperation and control of the environment elevate stress. Future research should emphasize coping process case studies, group phenomena roles, and classroom crowding. Nine notes and approximately 47 references are included.