The relationship between the Dietary Approaches to Stop Hypertension (DASH) diet and clinical, quality of life and mental health outcomes in migraine is unknown. To address this knowledge gap, we conducted a parallel-group, randomised controlled trial to evaluate the effect of the DASH diet on these health outcomes in women with migraine. Of 102 eligible women (20-50 years), fifty one randomised to the DASH and fifty one to the usual dietary advice (control) groups completed a 12-week intervention. The DASH diet was designed using a 7-d menu cycle to provide 15-20 % of total daily energy requirements from proteins, 25-30 % from fats and 55-60 % from carbohydrates. Dietary records and serum vitamin C levels were used to assess women's compliance with the DASH diet. The clinical symptoms of migraine (i.e., frequency, duration and severity) and quality of life and mental health (i.e., depression, anxiety and stress) outcomes were assessed in groups pre-and post-intervention. We observed greater decreases in the frequency (-3·00 v. -1·40, P = 0·025) and severity (-1·76 v. -0·59, P < 0·001) of migraine in the DASH v. control group post-intervention. Similarly, the DASH group exhibited a tendency towards greater decreases in migraine duration (-0·58 v. -0·33 d, P = 0·053) and had lower scores of depression (-4·50 v. -2·73, P = 0·019) and stress (-5·84 v. -2·98, P = 0·011) v. controls. However, the quality of life and anxiety outcomes remained comparable in groups post-intervention. Together, evidence supports the benefits of the DASH diet on improving migraine health outcomes in reproductive-aged women. Further research is needed to confirm our findings.