Drawing on one element of Jacobs' (1961) discussion of the social control benefits of "eyes on the street," this paper explores the link between the prevalence of active streets and violence in urban neighborhoods. Three distinct data sources from the Project on Human Development in Chicago Neighborhoods are merged to explore the functional form and potential contingency of the active streets-violence relationship: (1) video data capturing the presence of people on neighborhood streets; (2) longitudinal data on adolescents (ages 11 to 16) and their self-reports of witnessing severe violence; and (3) community survey data on neighborhood social organizational characteristics. Results from multilevel models indicate that the proportion of neighborhood streets with adults present exhibits a nonlinear association with exposure to severe violence. At low prevalence, the increasing prevalence of active streets is positively associated with violence exposure. Beyond a threshold, however, increases in the prevalence of active streets serves to reduce the likelihood of violence exposure. The analyses offer no evidence that the curvilinear association between active streets and violence varies by levels of collective efficacy, and only limited evidence that it varies by anonymity. Analyses of data on homicide and violent victimization corroborate these findings.