Firearm injuries are the leading cause of death among children aged 0 to 17 years in the United States. To examine the factors associated with recurrent firearm injury among children who presented with acute (index) nonfatal firearm injury in the St. Louis region. Multicenter, observational, cohort study. 2 adult and 2 pediatric level I trauma hospitals in St. Louis, Missouri. Pediatric patients aged 0 to 17 years presenting with an index firearm injury between 2010 and 2019. From the St. Louis Region-Wide Hospital-Based Violence Intervention Program Data Repository, we collected data on firearm-injured patient demographics, hospital and diagnostic information, health insurance status, and mortality. The Social Vulnerability Index was used to characterize the social vulnerability of the census tracts of patients' residences. Analysis included descriptive statistics and time-to-event analyses estimating the cumulative incidence of experiencing a recurrent firearm injury. During the 10-year study period, 1340 children presented with an index firearm injury. Most patients were Black (87%), non-Hispanic (99%), male (84%), and between the ages of 15 and 17 years (67%). The estimated risk for firearm reinjury was 6% at 1 year and 14% at 5 years after initial injury. Male children and those seen at an adult hospital were at increased risk for reinjury. Our data set does not account for injuries occurring outside of the study period and for reinjuries presenting to nonstudy hospitals. Children who experience an initial firearm injury are at high risk for experiencing a recurrent firearm injury. Interventions are needed to reduce reinjury and address inequities in the demographic and clinical profiles within this cohort of children. National Institutes of Health.