Introduction: Regular physical activity and quality sleep are considered key strategies for improving health and overall quality of life. Additionally, they prevent the onset of many chronic diseases, reduce stress, and enhance a person's psychophysical state. Students often do not give much importance to their health, including engaging in physical activity and quality sleep, due to changes in their environment and social circles, lack of time, and finding their first job. For this reason, it is important to assess the extent to which first-year students engage in sports and their sleeping habits, in order to ultimately raise awareness about the importance of these factors. The aim of the research: The aim of this research is to examine the correlation between sleep deprivation, physical activity, and overweight among first-year students at the Faculty of Dental Medicine and the Faculty of Electrical Engineering and Computing at the University of Zagreb. Methods: A cross-sectional study was conducted. The participants were first-year male and female students from the Faculty of Dental Medicine and the Faculty of Electrical Engineering and Computing in Zagreb. Data were collected using an anonymous questionnaire personally administered by the researcher at the School and Adolescent Medicine Clinic of the Dr. Andrija Štampar Teaching Institute of Public Health. The first part of the questionnaire consisted of sociodemographic data, the second part contained questions about the students' physical activity, and in the third part, they answered questions about their sleeping habits. Results: In this study, 193 students participated. The results showed that engaging in physical activity more than three times a week prevents early waking or difficulty falling asleep within 30 minutes. This positively impacts the prevention of obesity, as quality and sufficient sleep, combined with physical activity, help prevent the onset of obesity. Conclusion: Most students at the Faculty of Dental Medicine and the Faculty of Electrical Engineering and Computing engage in some form of physical activity, and the majority of them have a normal body weight. Regular physical activity contributes to better sleep quality and a normal BMI. Students who engage in sports multiple times a week will have a shorter sleep onset time, falling asleep within 30 minutes, and will not wake up in the middle of the night. Physical activity and quality sleep also have a significant impact on mental health and are considered key strategies against the development of depression and anxiety.