The ratio of non-high-density lipoprotein cholesterol to high-density lipoprotein cholesterol (NHHR) is an emerging lipid parameter. An association has been demonstrated with cardiovascular mortality. This study aimed to investigate the link between NHHR and mortality among hypertensive patients.This study utilized data from the National Health and Nutrition Examination Survey (NHANES) conducted in the United States from 1999 to 2018. The NHHR was derived from the lipid index. The association between NHHR and mortality in hypertensive patients was evaluated using multivariate Cox regression and Kaplan-Meier survival analysis, with restricted cubic spline curves (RCS) illustrating the nonlinear relationship. Subgroup analyses were conducted to assess the association's stability. The study included 16,259 patients with hypertension. Multivariate Cox regression analyses, adjusted for covariates, indicated that patients in NHHR quartiles Q2 and Q3 exhibited a 14% and 16% reduced risk of all-cause mortality, and a 32% and 33% reduced risk of cardiovascular mortality, respectively, compared to those in Q1. RCS analyses revealed a U-shaped relationship between NHHR and both all-cause and cardiovascular mortality in patients with hypertension. Subgroup analyses further maintained the robustness of this association across most subgroups. In hypertensive patients, NHHR exhibits a U-shaped relationship with both all-cause and cardiovascular mortality. This finding suggests that NHHR may serve as a new predictor of future mortality risk in hypertensive patients, providing a new marker for prognostic prevention in this special population.