Considerable research has illustrated the importance of exposure to violence and crime within the home and community for shaping adolescents’ behavioral/mental health outcomes, though gun homicide exposure has not been previously considered, largely because data on exposure to community gun violence has been limited. However, exposure to gun homicides may be uniquely harmful for adolescents’ mental health and behavioral development relative to other kinds of violent crime. In this study, we utilize newly-available data on the geocoded location of gun homicides that have been linked with restricted, longitudinal Fragile Families and Child Wellbeing data in order to examine whether exposure to gun homicides near adolescents’ homes and/or schools is associated with their mental health and externalizing behavioral problems. We additionally explore whether these relationships vary for adolescents who live closer to gun homicide incidents or for whom the gun homicide incident happened more recently. We utilize mixed effects models that account for lagged measures of adolescents’ mental health and behavior and characteristics of the individual, family, and residential context. We find that the occurrence of a gun homicide near adolescents’ homes or schools is associated with significantly worse symptoms of anxiety and depression for adolescent girls, but not boys, and these relationships vary depending on the distance and recency of a gun homicide. Our findings highlight the importance of providing coping resources for adolescents exposed to traumatic events in their communities and suggest that the benefits of addressing the gun violence epidemic will be understated without acknowledging its community-wide externalities.