Nonsuicidal self-injury (NSSI) is defined as a deliberate, self-inflicted damage to body tissue of a person in the absence of suicidal intent. It is very prevalent in adolescents worldwide and poses a threat to their health and survival. During adolescence, some people naturally have an increased tendency to take risks, seek feelings, and drive motivational changes in certain social contexts, which can lead to serious behavioral problems, such as NSSI, while most adolescents navigate the adolescence transition with minimal difficulties. As such, NSSI represents an emotion regulation disability in adolescents. According to the extant theories, NSSI functions as a means of escaping from undesirable emotional experiences, getting attention from, or sending a message to others. Most existing assessment instruments are self-reports of community adolescents evaluating NSSI function and topography. The best-known evidence-based interventions for NSSI are dialectical behavioral therapy and mentalization-based treatment.