Hypertension control remains a global challenge. Evidence on the association between adherence to the Dietary Approaches to Stop Hypertension (DASH) diet and blood pressure (BP) control in older Mediterranean populations is limited. We aimed to assess this association in Spanish older adults. This cross-sectional analysis included 371 participants (69 ± 9 years). Dietary intake was assessed using a validated 146-item food frequency questionnaire (FFQ), and DASH diet adherence was categorized as low, medium, or high. Multivariable logistic regression models were used to examine associations with BP control. Among participants with hypertension (n = 218), 52.8% achieved adequate BP control and consumed significantly more low-fat dairy products (+56%) and less sodium (-11%) than those with uncontrolled BP. The low adherence group had lower proportion of participants with controlled BP (21%) than the medium and high adherence groups (36% and 39%, respectively) (p < 0.05). Across increasing DASH diet adherence categories, systolic blood pressure (SBP) and diastolic blood pressure (DBP) were 4-5 mmHg and 3-4 mmHg lower, respectively. Medium adherence to the DASH diet was independently associated with substantially lower odds of uncontrolled BP (OR = 0.37; 95% CI: 0.16-0.82; p = 0.015). High adherence showed a similar magnitude of association but did not reach statistical significance. In this cohort of older Spanish adults, moderate adherence to the DASH diet was associated with meaningful improvements in BP control, suggesting that achievable, intermediate levels of DASH diet adherence may be sufficient to improve hypertension management in real-world settings. Longitudinal studies are needed to confirm causality and long-term cardiovascular benefits.