Background: Abnormal circadian blood pressure variation, particularly a non-dipper pattern, is associated with increased cardiovascular risk. Naples Prognostic Score (NPS) is a laboratory-based score that reflects the immune-inflammatory and nutritional status. Nevertheless, data regarding the relationship between NPS, circadian blood pressure patterns, and arterial stiffness in patients with newly diagnosed hypertension are limited. This study aimed to evaluate the relationship between blood pressure dipping status, the NPS, and arterial stiffness assessed by pulse wave velocity (PWV). Methods: This retrospective study included 297 newly diagnosed, untreated hypertensive patients who underwent 24-hour ambulatory blood pressure monitoring. Patients were classified as dipper (n = 145) or non-dipper (n = 152) according to nocturnal blood pressure decline. Laboratory parameters were recorded, NPS was calculated, and PWV was measured using a validated oscillometric device. Multivariate logistic regression analysis was performed to identify factors independently associated with non-dipper hypertension. Results: Non-dipper patients had significantly higher median NPS values compared with dippers [2 (0–4) vs. 1 (0–4), p < 0.001] and a higher prevalence of high NPS (score 3–4: 42.8% vs. 13.8%, p < 0.001). Median PWV was also significantly higher in the non-dipper group [7.70m/s (4.70–12.90) vs. 7.00m/s (4.40–11.20), p = 0.005]. After adjustment for clinically relevant covariates, both NPS (OR 1.71, 95% CI 1.19–2.47; p = 0.004) and PWV (OR 1.37, 95% CI 1.12–1.68; p = 0.002) were independently associated with non-dipper hypertension. Conclusion: In patients with newly diagnosed hypertension, a non-dipper blood pressure pattern is independently associated with higher systemic inflammatory burden and increased arterial stiffness. The NPS may serve as a simple and clinically applicable marker for early cardiovascular risk stratification in this population.