OBJECTIVES: We investigated the effect of family social and economic circumstances on intentional injury among adolescents. METHODS: We conducted a cross-sectional register study of youths aged 10 to 19 years who lived in Sweden between 1990 and 1994. We used socioeconomic status, number of parents in the household (1- or 2-parent home), receipt of welfare benefits, parental country of birth, and population density as exposures and compiled relative risks and population-attributable risks (PARs) for self-inflicted and interpersonal violence-related injury. RESULTS: For both genders and for both injury types, receipt of welfare benefits showed the largest crude and net relative risks and the highest PARs. The socioeconomic status-related PAR for self-inflicted injury and the PAR related to number of parents in the household for interpersonal violence-related injury also were high. CONCLUSIONS: Intentional-injury prevention and victim treatment need to be tailored to household social circumstances.