Due to the harmonization of the large volume of tasks that students face as an already particularly vulnerable population, they need a good ability to cope with crises including quality emotional regulation (Rückert, 2015). Cognitive strategies of emotional regulation contribute to the functioning of emotional regulation. A review of the available literature did not find research in the Republic of Croatia that would examine the relationship between optimism, pessimism, strategies of cognitive emotional regulation and mental health, nor the contribution of strategies of cognitive emotional regulation, optimism, and pessimism in explaining students' mental health. Given the above, the aim of this study was to examine the role of cognitive strategies, optimism, and pessimism in students’ mental health. The research was conducted on a sample of students throughout the Republic of Croatia in the period from January to February 2022. The results of correlation analyses and multiple regression analysis showed that mental health was significantly positively associated with optimism, while it was significantly negatively associated with pessimism. Also, a significant positive association was found between mental health and positive re-focusing, moving to planning, putting into perspective, and positive re-evaluation. On the other hand, a significant negative association was found between mental health and self-blame, rumination, and disaster. No significant association was found between mental health and acceptance and mental health and blaming others. Optimism, planning and putting into perspective have proven to be the only significant and positive predictors of mental health. This paper provides theoretical implications related to the complementarity of previous research with different outcomes and practical implications that can help in the formation of mental health prevention programs in the student, but also other populations.