The purpose of this study is to examine the effects of insecure attachment and complex trauma experiences of adolescents on self-injuring behavior. Special attention is given to whether or not the relationship between insecure attachment and complex trauma experiences is mediated by dissociative experiences. A total of 93 teenagers aged 14-19 who had experience in self-injury in Seoul and Gyeonggi-do, completed Experience in Close Relationship-Revised (ECR-R), Trauma Antecedents Questionnaire (TAQ), Adolescent Dissociative Experience Scale (A-DES), and responded to self-injuring behavior (frequency). The results of this study are as follows. First, correlation analyses showed positive correlations between insecure attachment, and complex trauma experiences of adolescents and their self-injuring behavior measured at the frequency of self-injury. In addition, dissociative experience showed significant positive correlations with self-injuring behavior. Second, dissociative experience proved to work a complete mediation on the effects of insecure attachment of adolescents on self-injuring behavior. Third, dissociative experience turned out to have a same effect in the case of complex trauma experiences of adolescents on self-injuring behavior. This suggests the need for intervention in dissociative experience above self-injuring behavior prevention and treatment of adolescents. Finally, the significance and limitations of this study and suggestions for further research were discussed.