Purpose: Epidemiological evidence suggests higher dietary flavonoid intake is associated with lower risk of several chronic diseases. This study aimed to investigate the association between intake of flavonoids and their subclasses, and incidence of hypertension among Australian women in two age cohorts. Methods: This population-based study included 6599 middle-aged (52.5 ± 1.5 years) and 6099 reproductive-aged (27.5 ± 1.5 years) women from the Australian Longitudinal Study on Women’s Health. Food frequency questionnaires were used to quantify intake of flavonoids by cross‐referencing with the Phenol-Explorer food composition database. Generalised Estimating Equation analyses investigated associations with incident hypertension, adjusting for demographic and dietary variables and hypertension risk factors. Results: There were 1645 cases (24.9%) of hypertension during 15 years follow-up in the middle-aged cohort and 336 cases (5.5%) during 12 years follow-up in the reproductive-aged cohort. Higher intakes of flavones [adjusted relative risk (ARR) for quintile 5 vs. 1: 0.82, 95% CI 0.70–0.97], isoflavones (0.86, 0.75–0.99) and flavanones (0.83, 0.69–1.00) were associated with a lower risk of hypertension in the middle-aged cohort. In the reproductive-aged cohort, higher intakes of flavanols (0.70, 0.49–0.99) were associated with a lower risk of hypertension. Key foods that provided these flavonoids were oranges, orange juice, apples, red wine and soy milk. Conclusion: Higher intakes of total flavonoids and subclasses were associated with a lower risk of hypertension in Australian women. These findings can be used in nutrition messaging and policies for improved cardiovascular health of women.