Background: Growing evidence indicates a link between unintentional injury and both disruptive and emotional psychopathology. We present further evidence of these associations and address the underlying mechanisms. We also examine the genetic contribution to unintentional injury. Methods: The Virginia Twin Study of Adolescent Behavioral Development provides genetically informative multi-wave and multi-informant data regarding common psychopathology using the Child and Adolescent Psychiatric Assessment interview. The EASI temperament scales and child injury involvement were measured in parent-report questionnaires. Results: Unintentional injury showed significant genetic effects in girls and significant shared environmental effects in boys and girls. Symptoms of over-anxious disorder (OAD), and the EASI temperament scales were independently associated with injury. Longitudinal modeling showed impulsivity and OAD symptoms were related prospectively to injury involvement. Injuries did not increase risk for later impulsivity or OAD symptoms but were related prospectively to separation anxiety disorder symptoms. Conclusions: Impulsivity and OAD symptoms increased risk of later injury. We discuss the processes that may be involved in these relationships.