Objectives: The aim of the study is to investigate the differences in the perception of the physical appearance in adolescents with developmental spinal deformities depending on the type of deformity, the use or non-use of orthoses, gender, age, and sports and recreation. Study Design: The study was designed as a cross-sectional study. Participants and Methods: The study was conducted on 100 adolescents aged 11 to 17 of both genders diagnosed with adolescent idiopathic scoliosis and kyphosis. An international body appearance self-assessment questionnaire (TAPS) and a self-administered anonymous questionnaire were used for the study. Results: The data from all 100 respondents were statistically analyzed. The average age of the respondents was 15 years. There were 78 girls and 22 boys who took part in the study. There were 80 adolescents with scoliosis and 20 adolescents with kyphosis. The mean TAPS score of all adolescents was 2.19±0.67, with a median of 2 and an interquartile range of 2 to 2.67. A statistically significant observed difference is that adolescents with kyphosis think their backs look nicer after sports and leisure activities (P=0.03). Adolescents who use orthoses are more likely to believe that they cannot engage in physical activity and sports due to their deformity, and this significantly affects their self-confidence (P=0.03). Adolescents who exercise and play sports in their free time perceive the asymmetry of their bodies significantly less than adolescents who do not exercise (P=0.02). Conclusion: There are differences in the self-assessment of physical appearance in adolescents with developmental spinal deformities depending on the type of deformity, the use or non-use of orthoses, gender, age, and participation in sports and recreation.