This study investigates the association between the triglyceride glucose (TyG) index and heart failure (HF) in a cross-sectional analysis of data from the National Health and Nutrition Examination Survey (NHANES) 2007–2018. The study included 13,825 participants, with 435 diagnosed with HF and 13,390 without HF. The TyG index, calculated as ln [fasting triglyceride (mg/dL) × fasting glucose (mg/dL)/2], was found to be higher in individuals with HF compared to those without HF (8.91 ± 0.74 vs. 8.57 ± 0.66, p < 0.001). Multivariate logistic regression models showed that the odds ratio (OR) for HF increased with higher TyG index levels, with an unadjusted OR of 1.644 and an adjusted OR of 1.057 in Model 4 (adjusted for all covariates). Restricted cubic spline analysis revealed a nonlinear dose-response relationship between the TyG index and HF risk, with a J-shaped curve. The optimal cutoff value for the TyG index was 8.91, with a sensitivity of 45.1% and a specificity of 70.2%. The study concludes that the TyG index is positively associated with the risk of HF and may serve as a therapeutic target and an important predictor of HF.This study investigates the association between the triglyceride glucose (TyG) index and heart failure (HF) in a cross-sectional analysis of data from the National Health and Nutrition Examination Survey (NHANES) 2007–2018. The study included 13,825 participants, with 435 diagnosed with HF and 13,390 without HF. The TyG index, calculated as ln [fasting triglyceride (mg/dL) × fasting glucose (mg/dL)/2], was found to be higher in individuals with HF compared to those without HF (8.91 ± 0.74 vs. 8.57 ± 0.66, p < 0.001). Multivariate logistic regression models showed that the odds ratio (OR) for HF increased with higher TyG index levels, with an unadjusted OR of 1.644 and an adjusted OR of 1.057 in Model 4 (adjusted for all covariates). Restricted cubic spline analysis revealed a nonlinear dose-response relationship between the TyG index and HF risk, with a J-shaped curve. The optimal cutoff value for the TyG index was 8.91, with a sensitivity of 45.1% and a specificity of 70.2%. The study concludes that the TyG index is positively associated with the risk of HF and may serve as a therapeutic target and an important predictor of HF.