The present study was conducted to investigate the efficacy of Mindfulness skills training on the cognitive fusion and irrational beliefs of female students with divorced parents. The present study was quasi-experimental with pretest, posttest, control group and two-month follow-up period design. The statistical population included high school female students with divorced parents in the city of Bandar Abbas in academic year 2019-20. 30 female students with divorced parents were selected through purposive sampling method and randomly accommodated into experimental and control groups (each group of 15 students). The experimental group received nine seventy-five-minute sessions of Mindfulness skills training during a month while one from the experimental group and two from the control were excluded from the study. The applied questionnaires included Cognitive fusion Questionnaire (Gillanders et al, 2010), and Irrational beliefs Questionnaire (Jones, 1961). The data were analyzed through mixed ANOVA via SPSS23 software. The results showed that Mindfulness skills training has significant effect on the cognitive fusion and irrational beliefs of the female students with divorced parents (p<0.001) in a way that this intervention has led to the decrease of cognitive fusion and the improvement of irrational beliefs in them. The findings of the present study implied that Mindfulness skills training can be used as an efficient method to decrease cognitive fusion and improve irrational beliefs in female students with divorced parents through applying techniques such as conscious thoughts, emotions and behaviors and being in the present.