Ashby St Mary is a village and civil parish in the English county of Norfolk. The civil parish has an area of 2.03 square kilometres (0.78 sq mi) and in the 2001 census had a population of 297 in 115 households, the population increasing to 316 at the 2011 Census. For the purposes of local government, the parish falls within the district of South Norfolk. The village was recorded in the Domesday Book. Thomas de Cottingham, a royal clerk who later became Master of the Rolls in Ireland was appointed rector of Ashby in 1349: he was notorious for pluralism.