This essay provides a critical examination of the definitions and dynamics of youth gangs. Particular attention is given to the identification of gangs (in the context of a wide spectrum of youth group formations) and the nature of gang membership (given that young people engage and affiliate with groups in variable ways). The essay also discusses the nature of gangrelated behaviour, outlines 9 propositions regarding the character and key features of gangs, and discusses the social construction of gangs as a problem.