Background The study aimed to determine the association between body mass index (BMI)‐for‐age and health‐related quality of life (HRQOL) among high school students in Tehran. Methods A total of 465 high school students (227 girls and 238 boys) and their parents were participated in this cross‐sectional study. Body weight and height of the students were measured. For assessing HRQOL, both adolescent self‐report and parent proxy‐report of the Persian version of Pediatric Quality of Life Inventory (PedsQL™4.0) questionnaire were completed by adolescents and their parents respectively. Results The prevalence of overweight and obesity (38.5%) was higher than severe thinness and thinness (2.8%). Mean of adolescent self‐reported and parent proxy‐reported HRQOL total score were 80.26 ± 12.07 and 81.30 ± 14.08 respectively. In terms of HRQOL subscale scores, the highest subscale score of HRQOL was reported in social functioning (87.27 ± 14.40) and the lowest score was reported in emotional functioning (69.83 ± 18.69). Based on adolescent self‐report, adolescent boys had significantly higher mean score for total and all subscale scores of HRQOL compared with girls (P < 0.05). BMI‐for‐age was inversely correlated to adolescent self‐reported HRQOL total score (r = −0.25, P < 0.05). Based on adolescents self‐report, HRQOL total score was significantly different by body weight status (F = 16.16, P < 0.05). Normal weight adolescents had significantly higher HRQOL total score compared with overweight (mean difference: 7.32; P < 0.05) and obese adolescents (mean difference: 9.10, P < 0.05). The HRQOL total score was not significantly different between normal weight and underweight adolescents (mean difference: 1.65, P = 0.96). However, based on parent proxy‐reports, HRQOL total score was not significantly different by body weight status (F = 2.64, P = 0.059). Conclusion More than one‐third of adolescents were overweight and obese. BMI‐for‐age was inversely correlated to adolescent self‐reported HRQOL. Based on adolescents' perspective, overweight and obese adolescents had poorer HRQOL compared with normal weight adolescents. Intervention studies are needed to improve the HRQOL of overweight and obese adolescents in Tehran.