The main purpose of this research is to examine the mediation role of interpersonal competence between parent and peer attachment and subjective well-being. The secondary purpose is to determine whether the relationships between the latent variables in the model differ on gender. A total of 462 students (229 male, 233 female) aged from 14 to 18 years old studying at five different high schools in a province in The Black Sea Region participated in the study. The mean age of participants in the study was 15.81 (S.D: 2.1). Parent and Peer Attachment Inventory, Adolescent Subjective Well Being Scale, and Interpersonal Competence Scale were utilized in data collection. According to the results of the study, it was found that three of the five dimensions of interpersonal competence, which is the variable tested for mediation, initiating relationship, asserting influence, and dimensions of resolving conflict except for self disclosure and providing emotional support partially mediated between attachment to parents and peers and subjective wellbeing. In addition, analyzing the relations between latent variables, it can be understood that the relationship between parent and peer attachment and interpersonal competence, as well as the relationship between parent and peer attachment and subjective well-being did not differ on gender. While there was a significant difference on behalf of men between interpersonal competence and subjective well-being, no significant difference was found on behalf of females between two variables. Research findings were discussed within the context of the related literature and some suggestions were provided for researchers and practitioners in the field of psychological counseling and guidance.