Background & Aims: Self-injurious behaviors as a part of rebellion in adolescence can affect mental disorders in adulthood and cause significant clinical distress, interpersonal and academic dysfunction (1). Studies have shown that 87% of teenagers involved in self-injurious behaviors had a psychiatric disorder (2). Most teenagers have not disclosed their self-injurious behavior due to fear of negative reactions from others (3). According to the conducted researches, inSECURE ATTACHMENT is mentioned as one of the underlying factors of self-injurious behaviors, so that 52% of patients with inSECURE ATTACHMENT style were more exposed to self-injurious behaviors, which causes helplessness and inability to solve interpersonal conflicts (9). Research results indicate a positive relationship between ambivalent and AVOIDANT ATTACHMENT styles and self-injurious behaviors (10, 11). People with an inSECURE ATTACHMENT style who suffer from self-criticism are prone to more damage when participating in social networks because they constantly compare themselves with others, and this comparison increases their insecurity and has a negative effect on their mental health (12). Among the therapeutic methods that deal with disturbing childhood experiences and transformational roots in a wide and wide way, we can mention schema therapy (17). By targeting underlying problems and awareness of emotional needs, schema therapy tries to learn healthy solutions and adapt to them through emotional, cognitive and behavioral techniques. Schemotherapy can correct the negative representations of the person's past towards important people in current relationships through open-ended parenting and empathic confrontation (18). Also, when patients show self-injurious behaviors, dialectical behavior therapy skills can be used (19). Dialectical behavior therapy is an evidence-based treatment method that has a significant effect in reducing self-injurious behaviors, and this is done by facilitating the acceptance of emotional responses, which is a useful therapeutic goal in reducing self-injurious behaviors (20). Due to the 10% prevalence of self-harm behaviors in the world population, it has been neglected and marginalized. No treatment has been found to be clearly superior to other treatments in reducing self-injurious behaviors, and more research is needed in this field. Therefore, the current research seeks to answer this question, is the combination of dialectical behavior therapy and schema therapy effective on self-injurious and ATTACHMENT behaviors? Methods: This research was conducted using a single-case experimental design based on a multiple baseline design using a stair-step method in Tehran. Three participants were selected by purposeful sampling and based on the entry criteria. Then, in three baseline stages, five intervention stages and three follow-up periods, they filled in Collins and Reed's ATTACHMENT style questionnaire, Young schema therapy and Sanson's list of self-injurious behaviors and received individual therapy during 28 sessions. Data analysis was done using the visual analysis method, and in order to determine the clinical significance, the percentage of recovery and the effect size were used. Results: The results showed that the combined treatment of dialectical behavior therapy and schema therapy was effective in increasing SECURE ATTACHMENT, reducing AVOIDANT and ambivalent ATTACHMENT, and reducing self-injurious behaviors. The total recovery rate of the subjects in SECURE ATTACHMENT was between 25% and 49% and in the reduction of self-injurious behaviors, it was more than 50%. Conclusion: The results of the present study showed that the combined treatment of dialectical behavior therapy and schema therapy was effective in increasing SECURE ATTACHMENT, reducing AVOIDANT and ambivalent ATTACHMENT. The results are consistent with the researches of Faskhudi et al. (2016), Alizadeh et al. (2014) and Tabbakuchian et al. (2016). In the explanation of the present research, it can be said that schema therapy leads to a feeling of safety in the person, that the person shows a safer ATTACHMENT style in his relationships and feels that there is someone who understands his feelings, pays attention to him and is available. Yes, there is a safe support and he can easily tell his needs and express himself without anxiety (31). In addition to this, dialectical behavior in all stages tries to show the different poles of an action to people and clients, how an emotion, thought or behavior can lead to the improvement of a process or its destruction. Other findings of the research indicate a decrease in AVOIDANT ATTACHMENT of clients. dialectical behavior therapy,Naming examines emotion recognition and conscious attention to emotions without judgment and is the goal of treatment,Therefore, it seems that the effective treatment process in the first and second references was done in this way. Other findings of the research showed that the ambivalent ATTACHMENT style had little improvement in the first clients and treatment failure in the second and third clients. From the research inconsistent with the present research regarding the effectiveness of schema therapy on reducing the ambivalent ATTACHMENT style, we can refer to the research of Danai Sage (34) and Uraki (35) and in line with the current research regarding the ineffectiveness of schema therapy on reducing the ambivalent ATTACHMENT style, we can refer to Amani's research pointed out (36). In schema therapy, by using open and borderline parenting techniques, an attempt has been made to change inSECURE ATTACHMENT to SECURE ATTACHMENT and adjust incompatible schemas, and it seems that the treatment effect in the first subject was done in this way. The results showed that the combined treatment of dialectical behavior therapy and schema therapy was effective in reducing self-injurious behaviors. The results are consistent with the research of Paclio et al. (37) and Mok (38). Hilden et al. (39). Dialectical behavior therapy is based on biosocial theory, which considers the inability to regulate emotions as an effective factor in self-injurious behaviors, which, by eliminating self-injurious behaviors, training more adaptive coping skills, helps to reduce emotional dysregulation and self-injurious behaviors in people. In addition, schema therapy has been used to resolve childhood traumatic events through cognitive and experimental techniques. Because in skematherapy, with the aim of establishing underlying problems and awareness of emotional needs, it provides the patient with healthier and more adaptive solutions through borderline and empathetic coping techniques and leads to the reduction of self-injurious behaviors. In the current research, it is necessary to point out limitations such as: the spread of the corona disease, the lack of necessary therapeutic communication when performing experimental techniques due to the use of masks, due to compliance with the health protocol. It can be concluded that the combined treatment of dialectical behavior therapy and schema therapy has been effective in increasing SECURE ATTACHMENT, reducing AVOIDANT and ambivalent ATTACHMENT, and reducing self-injurious behaviors. Therefore, it is suggested that the current research be used in the preventive educational format for teenagers in order to improve interpersonal relationships and increase social security and promote mental health.