Background: Hypertension is a major cause of cardiovascular diseases. Many studies have pointed out that the atherogenic index of plasma (AIP), which demonstrates plasma atherogenicity, is correlated with all-cause mortality, cardiovascular morbidity, atherosclerosis, and severity of coronary artery disease. Within this context, we tried to evaluate the correlation between nondipping circadian pattern and AIP. Methods: We enrolled 1,030 hypertensive patients (mean age: 53.6 ± 11.4) as part of the target population, separated into different groups based on the circadian blood pressure (BP) pattern taken from dipper and nondipper groups subsequent to 24-h ambulatory blood pressure monitoring (ABPM). We calculated the level of AIP using the log transformation of the ratio of triglyceride to high-density lipoprotein cholesterol. Results: The AIP observed in the nondipper group was remarkably higher than those of the dipper group (p < 0.001). After measuring the 24-h ABPM, we determined that AIP had a weak but significant correlation with nighttime systolic BP (r = 0.090, p = 0.004) and nighttime diastolic BP (r = 0.073, p = 0.019). As for the analysis based on the multivariate logistic regression, high AIP and age were found to be independently associated with the presence of the nondipping pattern. Conclusion: AIP levels are higher in patients with nondipping pattern compared to dipper patients. Additionally, higher levels of AIP are independently associated with the presence of the nondipping pattern in hypertensive patients.