Heytesbury, whose name indicates a Saxon origin, is situated on the north bank of the River Wylye, only a few miles from Warminster; the east-west Salisbury to Warminster road passes through it. Although small, the village was the centre of a hundred, and was part of a royal manor in 1086. Domesday also mentions its church, held by a priest with a Saxon name, which was given to Salisbury cathedral by Henry I ca. 1115, rebuilt, and converted to a collegiate church mid-century. During the reign of Stephen, Heytesbury was a residence of the Empress Matilda, who added to the endowments of the college.

Henry II granted the manor to Robert de Dunstanvill, lord of Castle Combe (Wilts.) in 1155. A successor, possibly Robert's grandson or, more likely, grand-nephew (descended from Robert's younger brother Reginald), Walter de Dunstanvill acquired licence for a Wednesday market and a May fair in 1215. This was evidently challenged from some quarter – perhaps the lord of Warminster (whose market was probably held on Saturdays) – for in 1223 the central government advised the sheriff of Wiltshire that the Heytesbury market had been ascertained not to be detrimental to others in the vicinity, and ordered him to have it proclaimed publicly and ensure it could be held, as it had formerly been, without obstruction, during the king's minority; after Henry III came of age, he confirmed the grant of market and fair (1227). Even though there is a reference to the men of Heytesbury being tallaged in 1168 as if their community were a town, it seems more probable that a borough was established in conjunction with the original market grant. The market was doing well enough so that when the wealthy soldier-politician Bartholomew de Badlesmere purchased the western part of the manor (essentially the borough) he felt it worthwhile paying to renew the licences in 1315, at the same time adding a September fair to the roster. The May and September fairs are still held today.

The outlines in the local topography of what appear to be burgage plots are practically the only indication we have of the location of a planned town, which was along the east-west through-road (now the High Street); a back lane on the north side of the burgages may support this for it bears the name of Newtown. The church stood on the south-west side of where the High Street was met by another road, connecting with small settlements to the south; the possible burgage clusters are on the east side of the church, on both sides of the through-road. The market presumably was held along this road, perhaps with a focus at the junction and even into that part of the large churchyard which fronted the street. This area was within the part of the manor acquired by Baron Badlesmere.

Lordship was divided in 1339, but reunited by the 1390s under the wealthy Hungerford family, which made Heytesbury the centre of its sheep-farming operations across the south-west, though the family's manor-house was to the east of the borough. Cloth-making is evidenced in the fourteenth and fifteenth centuries. However, whatever prosperity existed in a market town of no great significance could be sustained but not developed; Heytesbury did not expand much beyond its medieval core, which was largely destroyed by a fire in 1769, and, benefiting little from the Industrial Revolution, had reverted to village status by the nineteenth century.