Highlighting resource inequality, social processes, and spatial interdependence, this study combines structural characteristics from the 1990 census with a survey of 8,872 Chicago residents in 1995 to predict homicide variations in 1996–1998 across 343 neighborhoods. Spatial proximity to homicide is strongly related to increased homicide rates, adjusting for internal neighborhood characteristics and prior homicide. Concentrated disadvantage and low collective efficacy—defined as the linkage of social control and cohesion—also independently predict increased homicide. Local organizations, voluntary associations, and friend/kinship networks appear to be important only insofar as they promote the collective efficacy of residents in achieving social control and cohesion. Spatial dynamics coupled with neighborhood inequalities in social and economic capacity are therefore consequential for explaining urban violence.