BACKGROUND While dyslipidemia has been implicated in gestational hypertension (GH), individual lipid parameters show inconsistent associations. The total cholesterol to high-density lipoprotein cholesterol (TC/HDL-C) ratio may better reflect this association. This study assessed the association between the TC/HDL-C ratio and GH. MATERIAL AND METHODS This case-control study included 307 women with GH and 307 normotensive pregnant women as controls in China (2021-2024). Blood samples were collected after 20 weeks of gestation. The TC/HDL-C ratio was calculated and categorized into quintiles. Multivariable logistic regression models were used to examine the association between TC/HDL-C ratio and GH, adjusting for potential confounders. Restricted cubic splines (RCS) were employed to assess non-linear associations. Subgroup analyses were performed to evaluate whether this association varied among participants with different characteristics. RESULTS Higher TC/HDL-C ratio was positively associated with GH (odds ratio [OR]: 1.44, 95% confidence interval [CI]: 1.11-1.88, P=0.006), consistent across 3 models. The odds of GH progressively increased with rising quintiles of TC/HDL-C ratio. RCS curves revealed a linear relationship, with higher ratios associated with increased GH odds. Subgroup analyses showed that this association exhibited significant variations among subgroups stratified by hematocrit (HCT) and triglycerides (TG). CONCLUSIONS We found a positive association between TC/HDL-C ratio and GH; however, body mass index (BMI) was not available in this study, and this association may partly reflect underlying metabolic status, including adiposity, rather than a direct lipid-mediated effect.