Introduction Autoaggressive behavior in adolescence is a serious global problem and is associated with a wide range of psychopathological problems. Direct autoggressive behavior it can be divided into non-suicidal self-harm (NSSI) and suicidal behavior (which includes suicidal ideas, plans and attempts). Recent studies show that the range of global NSSI prevalence, among adolescents, goes up to 27% (Xiao et al., 2022), suicidal ideas up to 23%, and suicidal attempts up to 16% (Van Meter et al., 2023). These numbers indicate the seriousness of the problem. The most common risk factors for autoaggressive behavior include sociodemographic factors, family factors, history of abuse, and psychological/psychiatric factors. Some authors found the correlation between the emotional dysregulation and autoaggressive behavior among adolescents (Kranzler et al., 2016). In that context, autoaggressive behavior can serve them to express, validate or regulate their dysphoric emotions such as stress, anger, depression, or dissociation (Nixon et al.,2002). Family is listed as one of the most important predictors of autoaggressive behavior (Cassels et al., 2018), but also as an important factor in development of emotional regulation (Morris et al., 2007). Besides family functioning and emotional regulation, researches have found that identity development also has an important role in displaying autoaggressive behavior in a way that adolescents with more conflicted identity have higher tendency towards NSSI (Toukhy et al., 2022). However, most studies explored these correlations with simple models, and more comprehensive models, that include more than one or two factors, are missing. For that reason, this research seeks to cover all these relevant factors, and investigate their complex correlations with autoaggressive behavior. Aim and Research Problems The aim of this research was to investigate the role of emotional regulation, the development of identity, and family factors in autoaggressive behavior among adolescents with mental health problems. The research problems were: to determine the type of mental health difficulties in examined adolescents as well as presence of autoaggressive behavior; to determine the relative contribution of the family functioning, family communication, and family affective reactions in the explanation of autoaggressive behavior among adolescents; to determine relative contribution of identity development in adolescents with and without autoaggressive behavior; to explore the mediation effect of emotional regulation in the relationship between family factors and autoaggressive behavior as well as in the relationship between identity development and autoaggressive behavior. Method 100 participants were included in this study. Participants were 12 to 17 years old, 39 of them were boys, and 61 were girls. The participants were examined for the first time at the Psychiatric Hospital for Children and Youth by a child psychiatrist and were diagnosed with a mental disorder. Half of the participants displayed autoaggressive behavior, while the other half did not. The data were collected after a psychiatric assessment, and consent was obtained from the children and parents, using the paper-pencil method. Adolescents filled out self-assessment questionnaires, and parents a sociodemographic questionnaire. The following instruments were used in the survey: Youth Self Report (YSR; Achenbach and Rescorola, 2001), Assessment of Identity Development in Adolescence (AIDA; Goth et al., 2012a), Family Assessment Device (FAD; Epstein et al., 1983), Difficulties in Emotion Regulation Scale (DERS; Gratz and Roemer, 2004), Deliberate Self Harm Inventory (DSHI; Gratz, 2001) and a sociodemographic questionnaire. The adolescents filled up self report scales and parents answered the sociodemographic questionnaire. Data analyses included descriptive statistics, hierarchical regression analysis, with testing the mediation effects, and structural equation modelling (SEM). Results Most of participants in this research were diagnosed with emotional disorders with the beginning specifically in childhood and other emotional disorders in childhood. Participants who displayed autoaggressive behavior had higher anxiety and depression scores, displayed more withdrawal symptoms, more physical and social disabilities, thinking problems, attention problems, tendency to violate rules, and more aggressive behavior. Furthermore, the findings indicate a significant contribution of family functioning and discontinuity of identity in explaining the appearance of autoaggressive behavior. Adolescents who reported poor family functioning, as well as those with a higher score on discontinuity of identity, have expressed more autoaggressive behavior. Emotional regulation has proven to be a significant partial mediator in the relationships between family functioning and autoaggressive behavior as well as discontinuity of identity and autoaggressive behavior. In a structural model, the family functioning had a significant direct effect on autoaggressive behavior, but was not mediated by emotional regulation. However, relationship between discontinuity of identity and autoaggressive behavior was fully mediated by emotional regulation. The theoretical model had a good fit with observed data. Conclusion This study has shown that participants, who are prone to autoaggressive behavior often express multiple levels of other psychological difficulties. A significant role of family functioning and discontinuity of identity in predicting autoaggressive behavior, as well as the mediation effect of emotional regulation in these relationships, was confirmed. Such findings indicate an important role of family functioning, discontinuity of identity and emotional regulation in the development of autoaggressive behavior among adolescents, and provide an important scientific contribution though better understanding of the complex relationships between these factors. In addition, the findings also provide a valuable practical contribution, creating the foundation for the development of more efficient prevention programs for autoaggressive behavior among adolescents.