"Ashby" is a word of Anglo-Danish origin, meaning "Ash-tree farm" or "Ash-tree settlement". The Norman French addition dates from the years after the Norman conquest of England, when the town became a possession of the La Zouche family during the reign of Henry III.
Ashby de la Zouch Castle was built in the 12th century. The town and castle came into the possession of the Hastings family in 1464 and William Hastings, 1st Baron Hastings enhanced its fortifications from 1473. In the Civil War the town was one of the Royalists' chief garrisons under the control of Colonel Henry Hastings, 1st Baron Loughborough and commander of the North Midlands Army. When the town fell after a long siege in March, 1646 it was counted a great relief to the surrounding towns and villages.
Many of the buildings in Market Street, the town's main thoroughfare, are timber framed, but most of this is hidden by later brick facades. The Bull's Head public house retains its original Elizabethan half-timbering although most of this was plastered over some years ago and can now no longer be seen from the street. A short distance further down Market Street is a shop, currently occupied as a LOROS Charity Shop, which does retain its original Elizabethan timbers in full street view. There are also Regency buildings in this street. Bath Street has a row of Classical-style houses called Rawdon Terrace dating from the time that the town was a spa in the 1820s.
The local upper school, Ashby School, previously Ashby Grammar School, is a mixed comprehensive school for 14 to 18-year-olds that was founded in 1567. There were formerly two other endowed boys' schools of 18th century foundation.
A local high school, Ivanhoe College, for 11 to 14-year-old children, is named after the historical novel Ivanhoe by Sir Walter Scott which was set in the area of the castle. In Scott's novel the town hosts an important archery competition held by Prince John, in which Robin Hood competes and wins.