Aim: Although recognising insulin resistance (IR) in children is particularly important, the gold standard test used to diagnose it, the euglyceamic glucose clamp, is costly, invasive and is not routinely available in our clinical settings in Mexico. This study evaluated whether the triglyceride-glucose (TyG) index would provide a useful alternative. Methods: A total of 2779 school children aged seven to 17 years, from Durango, Mexico, were enrolled during 2015-2016. The gold standard euglyceamic-hyperinsulinemic clamp test was performed in a randomly selected subsample of 125 children, and diagnostic concordance between the TyG index and the homoeostasis model assessment of IR was evaluated in all of the 2779 enrolled children. Results: The best cut-off values for recognising IR using the TyG index were 4.65 for prepubertal girls and boys, 4.75 for pubertal girls and 4.70 for pubertal boys. Concordance between the TyG index and the homoeostasis model assessment of IR was 0.910 and 0.902 for the prepubertal girls and boys, 0.932 for the pubertal girls and 0.925 for the pubertal boys. Conclusion: The TyG index was useful for recognising IR in both prepubertal and pubertal children and could provide a feasible alternative to the costly and invasive gold standard test for IR in resource-limited settings.