The relationships between physical fitness, activity, and self-perceived fitness in adolescents in Hong Kong were investigated. Regular physical activity patterns, self-perceptions of fitness, and health-related physical fitness were measured in 201 secondary school students (M age = 13.8 yr.). The battery of fitness tests measured cardiovascular capacity, flexibility, muscular strength, muscular endurance, and body at composition. The boys had a higher self-perception of their own fitness and exercised more outside school than the girls. Participation in physical activity was related cardiovascular capacity, muscular strength, and body composition. Linear regression analysis indicated that exercise activity and body composition explained a portion variance in the subjects' self-perceived fitness. These findings highlight the connections between physical activity, fitness, and self-perception of fitness and consequently need for understanding the concept for better health-promotion strategies. [Reproduced with permission of author(s) and publisher from: Chan, E. W. C., Au, E. Y. M., Chan, B. H. T., Kwan, M. K. M., Yiu, P. Y. P., & Yeung, E. Y. Relations among physical activity, physical fitness, and self-perceived fitness in Hong Kong adolescents. Perceptual & Motor Skills, 2003, 96, 787-797. © Perceptual & Motor Skills 2003 Full article may be available at the publisher's website: http://ammonsscientific.com/link.php?N=4861]