The mediator factors of the relationship between menstrual symptom severity and mental health are still not well understood. Previous studies have suggested that evening chronotype and social jetlag are associated with poorer physical and mental health. This study aimed to examine the mediating roles of chronotype and social jetlag in understanding the relationship between menstrual symptom severity and mental health. The study was designed according to a predictive correlational model, and a total of 1,064 university students were included. To this end, one-way analysis of variance, path analysis, mediation analysis, and multiple regression analyses were performed. Menstrual symptom severity was significantly lower among morning-type individuals compared to intermediate and evening types. The total effect of the relationship between menstrual symptom severity and mental health level is 0.230. The indirect effects are 0.019 through the chronotype and 0.012 through the social jetlag. Our findings suggest that a morning chronotype may be associated with less severe menstrual symptoms. These results indicate the importance of investigating the effects of reducing chronotype, social jetlag, and menstrual symptom severity to improve the mental health of university students.