Introduction: Sleep is crucial for maintaining health, with its quality depending on factors such as duration and depth of sleep. Physical activity encompasses all movements that expend energy, while BMI (Body Mass Index) assesses body mass relative to height. The aim of this research is to determine if there is a correlation between these variables and sleep quality among students. Additionally, specific objectives include examining gender differences in sleep quality, physical activity levels, and BMI. Materials (Participants) and Methods: The data used in this study were obtained from the research titled "The Association of Physical Activity and Sedentary Lifestyle with Body Composition, Cardiorespiratory Capacity, and Spinal Postural Curvature in Young People" conducted in 2023. The sample consisted of students from the Faculty of Health Studies, the Medical Faculty, and the Faculty of Maritime Studies at the University of Rijeka (102 students; 60 women and 42 men). To assess sleep quality the Pittsburgh Sleep Quality Index (PSQI) was used, and for physical activity, the International Physical Activity Questionnaire (IPAQ). Results: The research did not find a correlation between body mass index (BMI) and physical activity with sleep quality. There is a difference in the level of physical activity based on gender. There is no difference in BMI based on gender. The hypothesis that there is no significant difference in sleep quality based on gender was confirmed. Conclusion: Although some hypotheses of this study were not confirmed, it concludes that physical activity and body mass index influence sleep quality. Further research is needed. It is important to develop and implement health programs that encourage the adoption of healthy lifestyles through healthy sleep habits and raise awareness of the importance of physical activity and maintaining an appropriate body weight.