Virtual communities enable one to pretend to be a different person or to possess a different identity at little or no cost. Despite the ubiquity of such communities, there is only limited theoretical and empirical research on how taking on a different identity is associated with one’s contributive behavior in those communities. Drawing on the social psychology literature, we adopt the concept of self-discrepancy rooted in self-identity and derive an index for self-discrepancy by using the differences between actual and virtual identities. Next, we link the self-discrepancy with perceived privacy rights and with quality and quantity of contribution. Analysis of 299 respondents showed that self-discrepancy significantly influenced perceived privacy rights and indirectly reduced quality and quantity of contribution in virtual communities. Furthermore, sub-group analysis revealed that the effects of self-discrepancy varied depending on whether the virtual community was utilitarian or hedonic. The present study aims to show how an individual member’s self-concept is associated with his or her psychological state in a virtual community, thereby offering practical insights for managers of virtual communities by suggesting how multi-identity should be managed therein.