Typically, the development of gang typologies have used either behaviorally based or structurally based characteristics to develop a classification system of gangs. The current study aims to assess the results of typologies approached from both angles, drawing from the same data source. It also examines whether using a combination of both approaches would prove to be useful. A separate but related aim of this study is to examine the boundaries between self-identified group members and gang members, especially on structural and behavioral characteristics. A hierarchical cluster analysis approach is used to group participants on both behavioral and structural measures using a sample of self-identified gang members (n = 44) and delinquent group members (n = 171). A number of important findings emerged from this analysis. First, the "types" of gangs and groups found were not differentiated based on membership status. Second, patterns found strongly depended on the chosen approach (behavioral or structural), but neither proved to be clearly superior. Instead, the choice between the two depends on the interest of the researcher. Finally, using a mixed approach appears to produce the most accurate picture and it does help differentiate between gang and group members more clearly. Yet, a much more complex picture of gangs and groups emerge, which suggests that a purely behavioral or structural classification may sometimes lead to oversimplification and misdirected policy interventions. (Published Abstract)