Helmdon is a village and civil parish about 4 miles (6.4 km) north of Brackley in West Northamptonshire, England. The village is on the River Tove, which is flanked by meadows that separate the village into two. The parish includes the hamlets of Astwell and Falcutt and covers more than 1,550 acres (630 ha). The 2011 Census recorded a parish population of 899.