Abstract Background and objective Due to the growing global trend of obesity, it is necessary to study the diet quality as a modifiable factor to reduce the dangerous consequences of obesity. Therefore, the aim of this study was to evaluate the association between meal-based diet quality index-international (DQI-I) with obesity in adults. Methods This cross-sectional study was performed on 850 men and women in Tehran (aged 20–59 y). Dietary intakes were assessed using three 24-h dietary recalls. Meal-based Diet quality was assessed based on the construction of DQI-I. The total DQI-I score ranged from 0 to 100, with higher scores denoting better diet quality. Multiple linear regression analysis was used to examine the association of DQI-I and BMI in each meal and Logistic regression analysis was used to examine the association of DQI-I and obesity in each meal. Results The mean (± SD) of age, body mass index (BMI), waist circumference (WC) and waist to hip ratio (WHR) were 42.35(± 10.90) years, 27.32(± 5.61) kg/m2, 89.09 (± 12.04) cm and 0.86 (± 0.11), respectively. In none of the meals, after adjusting for confounders, no significant difference in BMI was observed in the both women and men groups. After controlling of confounders, there was not any relationship between meal-based DQI-I and BMI resulted from multiple linear regression analysis also there was not any significant association between meal-based DQI-I and obesity resulted from Logistic regression analysis. Conclusion In this study, we did not find any significant association between meal-specified DQI with obesity. To reach the better evaluation, more prospective studies with large sample size are needed.