Nonsuicidal self-injury (NSSI) is a behavior that is prevalent among children and adolescents. Although NSSI is often associated with borderline personality disorder and depression, it co-occurs with numerous psychiatric symptoms and associated diagnoses. The current article reviews the research addressing psychiatric symptoms that are commonly found among children and adolescents who engage in NSSI, such as depression, anxiety, disordered eating, substance use, impulsivity, and suicide. Implications for the role of assessment by school mental health professionals are discussed.