Aim and Background: Fear of negative emotions plays an important role in maladaptive adjustment. When such emotions are experienced, individuals may be involved in emotional avoidance. Accordingly, the present study was conducted to investigate the role of mind wandering and mental time travel in predicting of fear of happiness. Methods and Materials: The research method was descriptive from type of correlation. The statistical population of this study was all students of Islamic Azad University of Birjand in the academic year of 2017-2018. The number of sample members in this study was considered to be 500. A cluster sampling method was used to select the sample. Data gathering was conduct using Fear of Happiness Scale (FSH), Mind Wandering Questionnaire (MWQ) and Mental Time Travel Scale (MTTS). Analyzing the data was carrying out by multiple regression. Findings: Findings showed that there is a positive and significant correlation between mind wandering and fear of happiness. Also, there is a negative and significant relationship between mental time travel (past and future) with fear of happiness. In addition, it was found that the fear of happiness were predicted through mind wandering, mental time travel in the past, and mental time travel in the future. The three models all account for over 19% of the variance fear of happiness (R Square= 0. 19). Conclusions: The findings of the present study showed the roles of mind wandering and mental time travel in predicting of fear of happiness. Therefore, considering the role of these predictive variables by experts, therapists and planners seem to be necessary when working with students, and particularly in counseling and therapeutic centers.