Background and Aim: Nowadays, to interpret health status, we do not simply rely on the measurement of a general index in a community rather we evaluate its distribution in various subgroups of the community. It has been proven that family socioeconomic status is associated with overweight and obesity in childhood and adolescence. This study aimed to determine the status of socioeconomic inequality in overweight / obesity and some related factors in adolescents. Materials and Methods: In this cross-sectional study, sample size was determined as 1440 students by stratified cluster random sampling. To collect the data we used demographic, socioeconomic status and nutritional status questionnaire. Height and weight of the participant was measured and the status of obesity was determined through calculating BMI. The concentration index and a concentration curve were used for the measurement of inequality. We used multinomial logistic regression to investigate the factors associated with obesity. The collected data was analyzed using Stata 11 software. Results: The mean age of 1445 students participating in the study was 16.35 ± 0.84 years. Of all, 51.63% (746 patients) were female and the rest were male. The mean BMI was 21.02 ± 3.31 in females, 21.57 ± 4.1 in males, and 21.28 ± 3.72 kg in all the participants. Concerning asset index,
Concentration Index for overweight/obesity was 0.09 in girls (95% CI: -0.14; 0.33), -0.02 in boys (95% CI: -0.14; 0.09), and 0.01 in the entire participants (95% CI: -0.13; 0.17). The odds of overweight/ obesity in males was 1.81 times more than that in females; the odds of overweight/obesity in those consuming a high-fat food was 1.61 time more than that in people not consuming a high-fat diet. Conclusion: Based on the results, obesity and overweight were more prevalent in adolescents with low socioeconomic level; this indicates the shift of the problem to the poorer groups of the community. Gender differences and the use of high-fat foods are among the variables affecting obesity and overweight, therefore it is necessary to pay special attention to this population group while designing health programs.