This study examined the influence of insecure attachment on adolescents’ samartphone addiction. This study also examined early maladaptive schemas may mediate the relationship between insecure attachment and samartphone addiction. To this end, a survey was conducted with 675 middle school students in Gyeongnam province. To identify the relation of these variables, the data were analyzed by structural equation modeling. The main findings of this are as follows: First, the anxious attachment of the adolescents had a positive influence on their smartphone addiction. Second, the insufficient self-control schemas of the adolescents had a positive influence on their smartphone addiction. Third, the insufficient self-control schemas had played a mediating role between the anxious attachment of the adolescents and their smartphone addiction. In sum, the anxious attachment of the adolescents was a significant predictor of their smartphone addiction, and indirectly affected their smartphone addiction through the insufficient self-control schemas. This results provide important implications for treatment and prevention strategies in counseling of smartphone addiction problems in adolescents. Finally, implications and limitations of this study are discussed.