This umbrella review summarizes the findings from 32 meta-analyses on the Triglyceride and Glucose (TyG) Index, assessing its diagnostic and prognostic value in various clinical settings. The TyG Index is calculated as the natural logarithm of fasting triglycerides multiplied by fasting glucose divided by 2. It reflects insulin resistance and is associated with multiple health outcomes. The TyG Index was significantly linked to an increased risk of contrast-induced nephropathy (CIN) and chronic kidney disease (CKD). It was also associated with higher risks of type 2 diabetes mellitus (T2DM), gestational diabetes mellitus (GDM), and diabetic retinopathy (DR). In metabolic diseases, the TyG Index was higher in patients with obstructive sleep apnea (OSA), metabolic syndrome, and non-alcoholic fatty liver disease (NAFLD). In cerebrovascular diseases, a higher TyG Index was associated with an increased risk of dementia, cognitive impairment, and ischemic stroke. For cardiovascular outcomes, the TyG Index was significantly associated with an increased risk of heart failure (HF), atrial fibrillation (AF), and hypertension (HTN). The review found that the TyG Index is a promising biomarker for screening and predicting various medical conditions, particularly those related to insulin resistance and metabolic disorders. However, the heterogeneity and methodological quality of the included studies suggest the need for further high-quality research to confirm these findings and refine the clinical utility of the TyG Index. The results of the meta-analyses showed significant associations between the TyG Index and various health outcomes, with varying levels of statistical power and epidemiological strength. The GRADE assessment indicated that the association between the TyG Index and most outcomes was of low or very low epidemiological strength.This umbrella review summarizes the findings from 32 meta-analyses on the Triglyceride and Glucose (TyG) Index, assessing its diagnostic and prognostic value in various clinical settings. The TyG Index is calculated as the natural logarithm of fasting triglycerides multiplied by fasting glucose divided by 2. It reflects insulin resistance and is associated with multiple health outcomes. The TyG Index was significantly linked to an increased risk of contrast-induced nephropathy (CIN) and chronic kidney disease (CKD). It was also associated with higher risks of type 2 diabetes mellitus (T2DM), gestational diabetes mellitus (GDM), and diabetic retinopathy (DR). In metabolic diseases, the TyG Index was higher in patients with obstructive sleep apnea (OSA), metabolic syndrome, and non-alcoholic fatty liver disease (NAFLD). In cerebrovascular diseases, a higher TyG Index was associated with an increased risk of dementia, cognitive impairment, and ischemic stroke. For cardiovascular outcomes, the TyG Index was significantly associated with an increased risk of heart failure (HF), atrial fibrillation (AF), and hypertension (HTN). The review found that the TyG Index is a promising biomarker for screening and predicting various medical conditions, particularly those related to insulin resistance and metabolic disorders. However, the heterogeneity and methodological quality of the included studies suggest the need for further high-quality research to confirm these findings and refine the clinical utility of the TyG Index. The results of the meta-analyses showed significant associations between the TyG Index and various health outcomes, with varying levels of statistical power and epidemiological strength. The GRADE assessment indicated that the association between the TyG Index and most outcomes was of low or very low epidemiological strength.