Physical fitness and morphological characteristics play a key role in the health, wellbeing and overall quality of an individual's life. With the increasing prevalence of a sedentary lifestyle and obesity among adolescents, it is important to understand the impact of playing sports on the morphological characteristics of high school students. The aim of this research is to investigate the differences in morphological characteristics between high school students who are actively involved in sports and those who are not, thus providing an insight into the potential benefits of playing sports during adolescence. The sample of respondents for the research on the differences in the morphological characteristics of high school students with regard to sports activity included a total of 99 students of the 1st Gymnasium in Osijek with an average age (16.77 ± 1.23 years), height (174.58 ± 19.37 cm) and mass (70.24 ± 12.37) . 9 tests were conducted, of which seven tests were related to morphological characteristics: body height, body weight, body mass index, visceral fat, body fat percentage, muscle percentage and basal metabolism, while two tests were survey type. All tests were performed in the Zrinjevac sports hall in Osijek during the physical and health education classes. The t-test for independent samples revealed a statistically significant difference between students who actively engage in physical activity and those who do not (p < 0.05) in the percentage of fat and percentage of muscle. A statistically significant difference was observed between students who want to enter the Faculty of Kinesiology and those who do not (p < 0.05) in height, fat percentage, muscle percentage and basal metabolism. Combining previous knowledge and the results of this research, it is clear that physical activity plays a key role in maintaining optimal body composition, health and well-being in children and adolescents.