INTRODUCTION: Obesity represents the major risk factor for development of insulin resistance during childhood and adolescents. In obesity, adipose tissue release free fatty acids, various hormones, and cytokines, resulting in insulin resistance. This study aimed to establish the correlation between vitamin D deficiency and the incidence of insulin resistance in obese children. DESIGN AND METHOD: This analytical cross-sectional study was arranged from December 2019 - February 2020 included 96 students aged 11 - 17 years old from junior and senior high school who met the criteria for obesity in Makassar. The study subjects were parted into two groups, obese children with vitamin D deficiency (levels of 25-hydroxyvitamin D ≤ 20 ng/ml) and obese children without vitamin D deficiency group (levels of 25-hydroxyvitamin D > 20 ng/ml). Data were analyzed using univariate and bivariate analysis. RESULTS: The frequency of insulin resistance in obese children with vitamin D deficiency was 28 (54.9%), while obese children without vitamin D deficiency was 10 (22.2%). Based on statistical analysis, the frequency of the occurrence of insulin resistance in vitamin D deficiency obese children was higher than in obese children without vitamin D deficiency with OR = 4.261 (95% CI 1.744 – 10.411), p = 0.001. CONCLUSION: The risk of insulin resistance in obese children with vitamin D deficiency is 4.261 times higher than obese children without vitamin D deficiency.