Despite the recognized importance of groups’ external contexts to their functioning, there is little research that fully explicates the relationship between groups and their environments. Instead, much extant research treats groups as closed systems. To advance the field’s understanding, we explore the treatment of the relationship between groups and their environments in existing literature by reviewing research that incorporates groups in naturally varying environments. We identify three predominant characterizations in the literature: the environment as a resource pool, as an impetus for change, and as a target. We offer a summary of the assumptions in these characterizations, a critical examination of each characterization, and develop a future research agenda that extends each characterization and challenges its key assumptions in an effort to explore the relationship between groups and their external environments.