PROJECT SUMMARY/ABSTRACT This proposal responds to RFA-CE-20-006, Objective One, Funding Option B. Firearm violence is an urgent public health problem. Despite declines in homicide and other violent crime, firearms were involved in the crime-related deaths of more than 140,000 people in the United States from 2008 to 2018. Youth in the juvenile justice system are disproportionately affected by firearm violence. Many juvenile offenders become parents when young; their children are likely to be at significant risk for firearm involvement and victimization. Yet there are remarkably few data on how parents’ involvement with firearms, during their own adolescence and young adulthood, influences their children’s risk. We designed Next Generation, funded by the National Institute of Child Health, Human Development the National Institute of Justice, and other agencies to address this and other key omissions. Leveraging prospective data already collected on our original participants, Next Generation includes the first prospective study of how high-risk parents’ current and past involvement with firearms (ownership, perpetration of violence, and victimization) influences that of their adolescent children. This study, however, samples only one child per family. We propose that the CDC augment our intergenerational study of firearms to add siblings. We propose to add 532 interviews: 165 with siblings and 367 additional interviews with their parents and secondary caregivers. Total N of the proposed study of firearms would then be 1,585: 709 children plus 544 parents and 332 secondary caregivers. Funding from the CDC will allow us to address three aims: Aim 1: to examine patterns of firearm involvement focusing on patterns of concordance and discordance between siblings. Aim 2: to examine the influence of parents’ (G1) firearm involvement on their children’s involvement (G2), focusing on differences between siblings in this relationship. Aim 3: to identify risk and protective factors that explain within- and between-family differences. The proposed prospective study has several key features: (1) the sample will include enough parents with a history of involvement with firearms (including victimization and perpetration) to examine the influence on their children and differences between siblings; (2) the sample is composed predominantly of socioeconomically disadvantaged African Americans and Hispanics, groups that face the most grievous consequences of firearm violence; and (3) the design will provide multilevel data to identify the risk and protective factors that explain why one sibling is able to avoid firearm involvement while the other is not. Findings will guide the development and adaptation of preventive interventions for the highest risk families. We will provide data responding to the CDC’s priority of identifying strategies to decrease inappropriate access to and use of weapons by minors and to prevent lethal violence.