Prevalence of insufficient physical activity and overweight is increasing rapidly worldwide. The consequences are particularly serious for youth because, in addition to endangering their health, they are lowering their quality of life. Therefore, it is not surprising that physical activity and nutrition are among the most common subjects of numerous studies in the recent years. The aim of this study was to examine the relationship between physical activity, body mass index and quality of life among adolescents. The study was conducted on 192 pupils of the third year of high school. Participants completed a questionnaire designed to collect anthropometric data, data on physical activity and quality of life. The results only partially confirmed the initial hypothesis. The results show that there is a positive association between total physical activity and quality of life and between total physical activity and body mass index. Significant correlation was not obtained between body mass index and quality of life. The level of physical activity in majority of young men and women is within the recommended values. Girls are most active in their leisure time, then in domestic affairs, and at least in sports, while the boys are most active in their leisure time, and less in sports and domestic affairs. The highest percentage of young men and women is within normal body weight. Results show that boys are significantly more physically active than girls in total physical activity and in sports and leisure, while the girls are significantly more active in the domestic affairs. More girls than boys are within normal body weight, compared to overweight, while there is no difference in quality of life between them.