Background/Objectives: Gestational hypertension is associated with increased maternal and fetal morbidity. The DASH diet is designed to reduce blood pressure and improve cardiovascular health. Our aim is to evaluate the efficacy of adherence to the DASH dietary pattern during pregnancy on the incidence of GH. Methods: PubMed, Scopus, Web of Science, Cochrane Library and Embase were systematically searched. All studies including data on the effect of the DASH diet on GH were included in this review. The study is registered in PROSPERO (CRD420251044348). Results: A total of five studies were included in our study. The meta-analysis reported a pooled relative risk (RR) of 1.03 (CI: 0.86–1.23) for the effect of the DASH diet on gestational hypertension. In the subgroup analysis for preeclampsia, the overall relative risk estimate was 0.78 (95% CI: 0.60–1.02). Both analyses did not yield statistical significance. Conclusions: Current evidence, although showing a favorable trend, does not conclude that the DASH diet reduces the risk of gestational hypertension, as the results did not achieve statistical significance. Although potential benefits have been observed, the limited number of available studies does not allow for definitive conclusions. More randomized and multicenter studies are needed to thoroughly investigate the relationship between the DASH diet and gestational hypertension in order to implement this dietary program instead of general dietary recommendations for GH.