Objectives: The purpose of this study is to investigate the effects on smartphone overdependence of out-of-school youths. Methods: This was a cross sectional study design using the out of school youth Panel Survey(2017). We conducted an empirical study consisting of 318 participants with using descriptive statistics, Pearson’s correlation coefficients, hierarchical multiple regression analysis to identify factors influencing smartphone overdependence. Results: Smartphone overdependence correlated positively with depression and carrier barriers such as lack of career informations, career development anxiety and financial difficulties. The main factors of smartphone overdependence in adolescents out of school were depression (β = .22, p = .002), gender (β = .21, p <.001), future anxiety (β = .15 , p = .0.0), subjective health status (β = .13, p = .028), smoking (β = .13, p = .032). Conclusion: Smartphone overdependence management programs for out-of-school youths should be included emotional and informational support to alleviate anxiety, fear of failing in one's career, as well as mental and psychological interventions to reduce level of depression.