Background: Obesity and Overweight at an early age can contribute with many chronic diseases such as cancers, diabetes and cardiovascular diseases. Diet-related inflammation is one of the most important underlying mechanisms that may has a key role in obesity and overweight. This paper aimed to compare the dietary inflammatory index (DII®) in normal weight and overweight adolescent boys. Methods: A total of 535 adolescent boys (214 cases were overweight and obese and 321 controls with normal weight) participated in this study from two schools in Tehran, Iran. The student's weight and body composition were measured using a Bio-Impedance Analyzer (BIA) scale. A validated semi-quantitative Food Frequency Questionnaire (FFQ) was used to assess dietary inflammatory index. Results: Results obtained from modeling DII® as a continuous variable identified a positive association between DII® and obesity (OR = 1.08, CI 1.01-1.16). After multivariable adjustment, subjects with DII® > 0.02 had at 1.5 times higher odds of obesity and overweight compared to subjects with DII® ≤ 0.02 (OR = 1.52; CI 1.04-2.22). Conclusion: Our study indicated the importance of dietary-induced inflammation in the obesity and overweight during adolescence. Therefore, advising adolescent to consume diet with lower DII® with more fruits and vegetables, rich sources of fiber, flavonoids, zinc, magnesium and selenium and avoiding the consumption of saturated fatty acids (SFA), trans-fatty acids, and cholesterol may support a healthy weight.