Antioxidant intake is inversely associated with different health outcomes; however, its association with insulin resistance (IR) has not been well documented. We hypothesized that the Dietary Antioxidant Index (DAI) is inversely associated with IR in Mexican children and adolescents. A cross-sectional analysis was performed using data from the Health Workers Cohort Study. A total of 830 children and adolescents aged 7 to 18 years were enrolled. The DAI was evaluated in three categories defined by tertiles using a semiquantitative food frequency questionnaire. IR was defined using previously reported cutoff points in the homeostasis model assessment. This association was evaluated using a multiple logistic regression model. Stratified analysis was performed using body mass index and sex. The prevalence of IR based on the DAI categories (low, medium, high) was 23.8%, 24.2%, and 15.3%, respectively. The IR odds ratio (OR) for participants in the highest DAI category was 0.49 (95% confidence interval [CI]: 0.30-0.80). Notably, female Children and Adolescents in the highest DAI category had significantly lower odds of developing IR than those in the lowest DAI category (OR 0.54, 95% CI 0.29-0.98). Participants with overweight/obesity showed a similar association (OR 0.37, 95% CI 0.18-0.76). These results suggest that the DAI is inversely associated with IR, particularly in females, highlighting the potential role of antioxidants in preventing IR. This underscores the need to establish recommendations for antioxidant consumption in female children and adolescents.