The manner in which a particular theoretical approach (the holistic, developmental, systems-oriented perspective) operates to integrate environmental psychology with other subfields of psychology-including clinical, developmental, health, organizational, personality, and social-is described. This serves to advance these and other subfields of psychology and to mitigate the ongoing fragmentation in psychology. Integration is evident in the implications of the assumptions of the perspective for empirical studies, originating largely as theoretical and practical problems for environmental psychology, that have impact on and are of interest to a variety of subfields of psychology.