The triglyceride-glucose (TyG) index is a reliable marker of insulin resistance that is involved in the progression of hypertension. This study aimed to evaluate the association of the TyG index with the risk for major cardiovascular events (MACE) in young adult hypertension. A total of 2,651 hypertensive patients aged 18-40 years were consecutively enrolled in this study. The TyG index was calculated as Ln [triglycerides × fasting plasma glucose/2]. The cutoff value for an elevated TyG index was determined to be 8.43 by receiver-operating characteristic curve analysis. The primary endpoint was MACE, which was a composite of all-cause death, non-fatal myocardial infarction, coronary revascularization, non-fatal stroke, and end-stage renal dysfunction. The secondary endpoints were individual MACE components. During the median follow-up time of 2.6 years, an elevated TyG index was associated with markedly increased risk of MACE (adjusted hazard ratio [HR] 3.440, P < 0.001) in young hypertensive adults. In subgroup analysis, the elevated TyG index predicted an even higher risk of MACE in women than men (adjusted HR 6.329 in women vs. adjusted HR 2.762 in men, P for interaction, 0.001); and in patients with grade 2 (adjusted HR 3.385) or grade 3 (adjusted HR 4.168) of hypertension than those with grade 1 (P for interaction, 0.024). Moreover, adding the elevated TyG index into a recalibrated Systematic COronary Risk Evaluation 2 model improved its ability to predict MACE. An elevated TyG index is associated with a higher risk of MACE in young adult hypertension, particularly in women and those with advanced hypertension. Regular evaluation of the TyG index facilitates the identification of high-risk patients.