Ashby St Mary, historically Ascebei, is a small 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 in 120 households at the 2011 Census. For the purposes of local government, the parish falls within the district of South Norfolk.