The aims of this study were twofold: a) firstly, identify secondary school students (6th, 7th, and 8th grades) whose needs differ in physical education and sport courses according to their level of HRF knowledge and Stages of Change (ESC) and b) secondly, examine the needs of identified groups. This was a mixed-method study that involved two phases of data collection. In the first phase, the Exercise Stages of Change Questionnaire and Health-Related Fitness Knowledge Test were applied to all 6th, 7th, and 8th grade students in one school (n= 511, 233 girls, 278 boys). Based on their scores, students were divided into four groups: ''Group 1: High HRF knowledge level and ESC'', ''Group 2: High HRF knowledge level and low ESC'', ''Group 3: Low HRF knowledge level and high ESC'', and ''Group 4: Low HRF knowledge level and ESC''. In the second phase, the study was focused on identifying the different needs of students in these groups regarding physical activity and health in the classroom environment. Four focus group interviews were conducted with 30 students (13 girls, 17 boys), selected through purposeful sampling from these four groups. The study found significant differences in the physical activity behaviors of students in the four different groups based on their HRF knowledge and ESC. In order to help students develop active and healthy lifestyles, it is recommended that physical education teachers take into account these groups and their specific needs, group students accordingly, and structure the classroom environment accordingly.