Non-suicidal self-injury (NSSI) is a significant public health concern, with severely impacts for adolescent mental health. As awareness of the harmful effects of NSSI grows, there is an increasing emphasis on understanding the underlying mechanisms in this age group. This study explores how internalizing and externalizing issues related to parent-child conflict influence NSSI, focusing on the roles of negative self-perception (self-criticism) and association with deviant peer affiliation in this relationship. We used questionnaires to assess variables including parent-child conflict, self-criticism, Deviant peer affiliation, internalizing and externalizing issues, and instances of NSSI. A conditional process model was employed to examine the interrelated pathways through which these factors influence each other. A total of 804 adolescents successfully completed the questionnaires. Our analysis revealed that the severity of NSSI was positively associated with the level of parent-child conflict (b = 0.22, p < 0.001). Self-criticism and internalization issues, as well as deviant peer affiliation and externalizing issues, acted as dual mediators in this relationship, explaining 17.72% and 7.93%, of the variance, respectively. Among the examined analyzed, the influence of parent-child conflict on NSSI through deviant peer affiliation was not statistically significant. This study highlights the significant relationships between parent-child conflict and NSSI in adolescents. This relationship is mediated by a dual-chain involving self-criticism and internalization issues, as well as deviant peer affiliation and externalizing issues, all of which are identified as risk factors for NSSI. Understanding these dynamics can inform the development of targeted interventions to reduce NSSI among adolescents.