Key PointsQuestionAre community-level factors and state-level gun laws associated with rates of firearm-related deaths in children and adolescents?FindingsIn this cross-sectional study including 5813 youths aged 10 to 19 years who died of an assault-related firearm injury, death rates increased in a stepwise fashion with increasing community-level social vulnerability; this trend persisted among all types of state gun laws. States with restrictive gun laws had lower rates of assault-related firearm deaths among youths; however, youths from socially vulnerable communities were disproportionately impacted across the spectrum of state gun laws.MeaningThese findings suggest that legislation may not be sufficient to solve the problem of assault-related firearm deaths among children and adolescents.