Recent evidence, showing that gender differences in depression and antisocial behavior originate in early adolescence, points to the importance of socialization and dimensions of the self in understanding the higher rates of internalizing disorders among females and higher rates of externalizing disorders among males. We review theories and research that link gender stratification to dimensions of the self and, through this, to gender differences in disorders. These theories and evidence further suggest that girls and boys differ in the boundaries drawn between the self and others. Ranging from high degrees of connectedness to high degrees of separation, such boundaries are conceptualized as people's basic operating assumptions about social relationships. An analysis of empathy provides a preliminary test of the contribution of boundary assumptions to explaining gender differences in internalizing and externalizing disorders.