Self-rated health (SRH) is a tool for assessing a population's health across the lifetime, and seems to be a dynamic assessment of current health status and a strong predictor of cardiovascular disease and mortality, whereas insufficient levels of physical fitness in adolescence are a significant health problem and may contribute to the development of many disorders in adulthood. In this cross-sectional study, we attempted to assess the relationship between SRH and the physical fitness of adolescents. Two hundred and thirty-five adolescents (eighty-five boys and one hundred and fifty girls) aged 16-17 were recruited for this study. The study procedures included a short author questionnaire and physical fitness assessment (Zuchora's Physical Fitness Index). Boys declared better health states and reported less frequent morbidity of seasonal diseases ( < 0.05). No differences were found in physical fitness, the incidence of postural disorders, lower limb malalignments, foot deformities, sleep duration, and perception of physical activity on physical condition and well-being in boys and girls ( > 0.05). The comparison of physical fitness levels in adolescents with different SRH, sleep duration, perceptions of physical activity on physical condition and well-being also showed significant differences ( < 0.05). Positive SRH and perception of physical activity on physical condition and well-being, proper sleep duration (7-8 h/night), and a lack of foot deformities are associated with a better physical fitness in adolescents. Physical fitness seems to be a good predictor of SRH only in Polish boys, but not girls and the entire population. The lack of significance in the entire population could be attributed to the substantial number of girls in the study group. Despite that, it is recommended to encourage adolescents to engage in regular exercises, sleep routines and healthy lifestyles. Further research should be based on a more representative group, with a comparable number of girls and boys in the study group and potential confounders, but also they should be focused on SRH predictors to improve SRH in Polish girls.