Gang research has spanned nearly a century. In that time, we have learned that gang membership increases the chances of involvement in homicide as a victim or offender. The violence that embroils gang life, both instrumental and symbolic, often has consequences. In this paper we review the gang homicide literature covering topics such as definitional issues, available data, correlates and characteristics, and theoretical explanations. The review examines individual, group, and structural contexts for gang homicide. We conclude with a discussion of future needs in theory, data, and methods, to improve our understanding of gang homicide.