Although the notion of identity has received substantial attention from sociologists and psychologists, it has not been well developed in the gang literature. Identity accounts for a person's sense of self, which is based on meaningful social interactions and group participation, and becomes a source for publicly performing social roles. Gang membership is one such role that merits significant attention, and existing theories about identity and role performance can help explain variations in criminal behavior among members. This article applies multiple perspectives on social, personal, and collective identity to gangs and gang members. It offers principles to explain how gang identities fuel social performances that mimic, induce, or involve criminal behavior.