We investigated whether high adherence to the Dietary Approaches to Stop Hypertension (DASH) diet was independently associated with lower risk of incident hypertension. Participants included 5632 adults, without hypertension at the baseline (2008–2010) of the Longitudinal Study of Adult Health, who took part in the second follow-up visit (2012–2014). Adherence to the DASH diet was estimated at baseline using a score based on eight food items (final scores from 8 to 40 points) and was categorised as high adherence (≥30 points, or ≥75 %) and low adherence (<75 %; reference). Hypertension was defined as systolic blood pressure (BP) ≥140 mmHg or diastolic BP ≥90 mmHg, or use of antihypertensive drugs. The association between adherence to the DASH diet and the risk of incident hypertension was estimated using Cox regression models adjusted by covariates. In total, 780 new cases of hypertension (13·8 %) were identified in about 3·8-year follow-up. Participants with high adherence to the DASH diet had 26 % lower risk of hypertension (hazard ratio (HR) 0·74; 95 % CI 0·57, 0·95) after adjustment for socio-demographic characteristics, health-related behaviours, diabetes and family history of hypertension. The HR reduced to 0·81 (95 % CI 0·63, 1·04) and was of borderline statistical significance after adjustment for BMI, suggesting that lower body weight explains about 10 % of the association between high adherence to the DASH diet and hypertension risk reduction. The results indicate that high adherence to the DASH diet lowered the risk of hypertension by one-fourth over a relatively short follow-up period.