Purpose: Although a significant proportion of type 2 diabetes mellitus (T2DM) cases arose from normal-weight individuals, studies on indicators that can predict T2DM in normal-weight people are limited. Accordingly, this study aims to investigate the predictive value of obesity indices and triglyceride glucose related parameters (TyG-related parameters) in T2DM among normal-weight Chinese elderly.Methods: A total of 24,215 normal-weight Chinese elderly (age ≥ 60 years) [body mass index--BMI (18.5-23.9 kg/m2)] were included. Obesity indices and triglyceride glucose related parameters (TyG-related parameters) included waist circumference (WC), waist-to-height ratio (WHtR), visceral adiposity index (VAI), lipid accumulation product (LAP), and TyG-related parameters (TyG, TyG-BMI, TyG-WC, and TyG-WHtR). Multivariate logistic regression analysis was performed to examine the associations between obesity-and TyG-related indices and T2DM. The areas under the curve (AUC) of the receiver-operating characteristic (ROC) curve analyses were used to evaluate and compare the predictive value of the different indices. Results: The prevalence of T2DM was 14.2% in normal-weight individuals. Among the indices, TyG was significantly associated with T2DM among men and women, respectively (adjusted odds ratio--aOR 19.005; 95% CI 13.235–27.291) and (aOR 25.262; 95% CI 16.957–37.634). Compared with other indices, TyG had the highest AUC value for T2DM in men (AUC: 0.818, 95% CI 0.810–0.825) and women (AUC: 0.824, 95% CI 0.814–0.833).Conclusions: TyG is an effective marker and outperforms than other indices when predicting T2DM in the normal-weight Chinese elderly population.Level of evidence: Level V