Objective: This study was conducted to study the role of personality traits and early maladaptive schemas (EMS) in predicting mental health in high school students. 

Methods: A correlational descriptive study was conducted. Four hundred high school students in Urmia were selected by random multistage cluster sampling. In order to collect data, the General Health Questionnaire for mental health (GHQ), the NEO Five Factor Inventory (NEO–FFI) for personality, and Young’s cognitive schemas were administered.  Data analysis was done with Pearson’s correlation, multivariate regression test, and t-test, using SPSS software. 

Results: Neuroticism (N), which is an indication of emotional instability, was high in the studied subjects. The latter indicates that they have weak adaptive states. The greatest amount of variance in mental health was observed in the (N) subscale –a personal trait variable– at 23% and 10% (in girls and boys, respectively). Moreover, the variance observed in the rejection/disconnection subscale –an EMS variable– was observed at 27% and 11% (in girls and boys, respectively) (p<0.05).

Conclusion: Early maladaptive schemas and personality traits play important roles in predicting mental health (p<0.05).