The present study was designed to explore the effects ofGAS6andAXLgene polymorphisms on adiposity, systemic inflammation, and insulin resistance in adolescents. After multistage sampling from the data of the Taipei Children Heart Study-III, we collected 358 boys and 369 girls with an average age of 13.3 years. We genotyped the adolescents’GAS6rs8191973,GAS6rs8191974,AXLrs4802113, andAXLrs2304232 polymorphisms. Significantly higher body mass index (BMI), waist circumference (WC), and hsCRP levels were found in boys with the GG genotype ofGAS6rs8191974 than A allele carriers; higher IL-6 and insulin levels and increased HOMA-IR were found in boys with the GG genotype ofAXLrs2304232 than the A allele carriers. There was a significant difference in hsCRP levels of boys with the TT, TC, and CC genotypes ofAXLrs4802113. Boys with both the GG genotype ofGAS6rs8191973 and the GG genotype ofGAS6rs8191974 exhibited higher BMI, WC, IL-6, and hsCRP levels than the boys carrying both the C allele of theGAS6rs8191973 and the A allele of theGAS6rs8191974. In conclusion,GAS6andAXLpolymorphisms are associated with adiposity, systemic inflammation, and insulin resistance in adolescents, especially in boys.