Amesbury Abbey was a Benedictine abbey at Amesbury in Wiltshire, England, founded by Queen Ælfthryth in about the year 979 on what may have been the site of an earlier monastery. The foundation was dissolved in 1177.
The abbey church has survived as the Church of St Mary and St Melor, a Grade I listed building. The name Amesbury Abbey is now used by a nearby mansion, which has since been converted into a nursing home. This house is also Grade I listed.
Ælfthryth founded two religious houses at about the same time, the other being at Wherwell in Hampshire. Her motive was long believed to be contrition for the murder of Edward the Martyr, making the date of 979 given by the Melrose chronicle appropriate. However, she is now considered not to have been personally responsible for the murder.
Amesbury was already a sacred place in Pagan times, and there are legends that a monastery existed there before the Danish invasions. There may have been an existing cult of St Melor which led Ælfthryth to choose Amesbury. Melor, the son of a leader of Cornouaille and a boy-martyr, was buried at Lanmeur and venerated in Brittany, but a later tradition claims that some of his relics were brought to Amesbury and sold to the abbess. Edward was another boy-martyr. However, the 12th-century life of St Melor says the nunnery at Amesbury was founded before Melor's relics arrived. At the time of the Domesday Book (1086), the abbey held, as it had in King Edward's time, the Wiltshire manors of Bulford, Boscombe, Allentone, Choulston, and Maddington, totalling twenty-seven hides, plus the manor of Rabson in Winterbourne Bassett. In Berkshire it held Ceveslane in Challow, Fawley, and Kintbury and the church at Letcombe Regis.