Background & Aims: Many students experience high levels of stress during their studies, causing them a lot of psychological damage and leading to feelings of inefficiency and a negative self-critical attitude. In this regard, the current study aimed to evaluate the effectiveness of mindfulness-based stress reduction group training on the self-critical attitude of female students with academic stress at Farhangian University of Chaharmahal and Bakhtiari Province, Iran. Methods: The present quasi-experimental study was carried out with a pretest-posttest design and a control group. The statistical population of this study included all 350 female students of Farhangian University of Chaharmahal and Bakhtiari province in the academic year 2018-2019. Among all the students, 150 students were selected by random sampling, and then out of them 60 students with higher academic stress scores than the average group were selected as the final sample and randomly divided into two groups (i.e., experimental group [n=30] and control group [n=30]). In both groups, the self-critical questionnaire was completed as a pretest, and after the intervention, the posttest and two-month follow-up were performed again for both groups. The collected data were analyzed using descriptive statistics (e.g., mean and standard deviation) and inferential statistics (e.g., analysis of covariance) by SPSS software (version 23). Results: Based on the obtained results, mindfulness-based stress reduction group training had a significant effect on self-critical reduction (eta=7.27; F=30.6; P<0.001). Conclusion: According to the findings of this study, mindfulness-based stress reduction training can be used in order to decrease studentsʼ self-criticism