Background and aims: Subjective well-being as a major prerequisite of health ensures mental and physical health, a long life, happiness, improved quality of life, and higher socioeconomic indices. The present study aimed to investigate the effectiveness of mindfulness-based cognitive therapy (MBCT) and acceptance and commitment therapy (ACT) on subjective well-being, psychological distress, and emotion regulation in medical science students. Methods: The statistical population of this semi-experimental comprised all female students at Kerman University of Medical Sciences (Iran) in the academic year of 2019-2020. Forty-five students referring to the university counseling center were selected as the sample of the study using convenience sampling and randomly divided into two experimental groups and a control group (n=15 per group). The first and second experimental groups underwent eight 90- and 45-sessions (twice a week) of MBCT and of ACT, respectively. The research instruments included the Subjective Well-being Scale (SWS), the Depression, Anxiety, and Stress Scale, and the Cognitive Emotion Regulation Questionnaire. Results: The results showed that MBCT and ACT were effective in improving the components of subjective well-being and emotion regulation in medical students (P<0.001). Moreover, MBCT and ACT significantly reduced the post-test scores of psychological distress subscales in the experimental group compared to the control group (P<0.001). Finally, no difference was observed between the two therapies in terms of effectiveness. Conclusion: According to the results, MBCT and ACT effectively promoted female students’ subjective well-being and emotion regulation and alleviated their psychological distress.