Abstract: Knowledge is a determining factor for the development of postural habits; it could be considered as the first step in the establishment of changes. The aim of this study was to analyze the level of specific back-health-related physical activity and exercise knowledge in adolescents. A cross-sectional study was conducted on a sample of 1500 high school students between the ages of 13 and 18 (mean age = 15.18   1.44). Students from the Valencian Community (Spain) were recruited with a confidence level of 95% and an accepted standard error of   2.53%. Self-report questionnaires were used to record back-health-related physical activity knowledge. The level of specific knowledge of back-health education related to physical activity and exercise in adolescents was low (X = 2.05   2.26). Only 10.9% of the students passed the specific knowledge test, achieving a score equal or superior to 5. The boys' average score was higher (X = 2.17   2.31) than the girls' (X = 1.94   2.21) with statistically significant differences (p = 0.048). The level of specific knowledge increased with age (p < 0.001). Secondary school students show a low level of specific knowledge concerning back health. It is recommended that back care education be a part of school curriculum.