Background: The relationship between adolescent obesity and eating disorders is an issue that needs urgent attention. Screening for eating disorders is as important as dietary interventions to treat obesity. This study aimed to determine the relationship between hedonic hunger, food addiction, and night eating syndrome, which are considered potential risk factors for obesity, and body mass index (BMI) in adolescents. Methods: The data were collected through an online questionnaire. The “Power of Food Scale (PFS)” was used to assess hedonic hunger; the “Yale Food Addiction Scale for Children 2.0 (dYFAS-C 2.0)” was used to assess food addiction; and the “Night Eating Questionnaire (NEQ)” was used to assess night eating syndrome (NES)”. BMI was calculated using self-reported height and weight values of adolescents. The mediated structural model analysis was performed to evaluate the effect of hedonic hunger on BMI z score via food addiction and NES. Results: The study was conducted with 614 voluntary adolescents aged between 11 and 18 years. The dYFAS-C 2.0 and NEQ scores were found to be higher in adolescents with overweight and obesity, and the BMI z-score of the adolescents had significant positive correlation with their PFS scores (p <.001). Hedonic hunger has no direct effect on BMI independent of food addiction and NES (β = − 0.051, p =.468), but when the total indirect effect is evaluated with the bootstrap analysis, it was found that one-unit increase in hedonic hunger score increases BMI z-score by approximately 0.22 units (β = 0.223, SE = 0.046, 95% CI 0.131–0.313). Hedonic hunger, food addiction, and NES together explained 5.2% of the total variance in BMI z score. Conclusion: This study showed that hedonic hunger significantly predicted BMI z-score in adolescents through food addiction and NES. This emphasizes the critical importance of evaluating adolescents in terms of hedonic hunger, food addiction, and NES in the prevention, diagnosis, and treatment of obesity.