Ashby-de-la-Zouch (/ˈæʃbi də lə ˈzuːʃ/), also spelled Ashby de la Zouch, is a market town and civil parish in the North West Leicestershire district of Leicestershire, England, near to the Derbyshire and Staffordshire borders. Its population at the 2021 census was 16,491. Ashby de la Zouch Castle was an important fort in the 15th to 17th centuries. During the 19th century, the town's main industry was ribbon manufacturing.

The civil parish includes the hamlets of Shellbrook to the west and Boundary to the north-west. Swadlincote, Burton upon Trent, Melbourne and Coalville are within 10 miles (16 km), with Derby 12 miles (19 km) due north. It lies at the heart of the National Forest, 24 miles (39 km) south of the Peak District National Park, on the A42 between Tamworth and Nottingham.

The town was known as Ashby in 1086. This is a word of Anglo-Danish origin, meaning "Ash-tree farm" or "Ash-tree settlement". The Norman French name extension dates from the years after the Norman conquest of England, when Ashby 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 First English Civil War, the town was one of the Cavaliers' chief garrisons under the control of Colonel Henry Hastings, 1st Baron Loughborough and commander of the North Midlands Army and was where Charles I and his cavalry retreated to after the defeat at Naseby. 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. Most of this structure 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 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 retains its original Elizabethan timbers in full street view. Regency buildings are also standing in this street. Bath Street has a row of Classical-style houses called Rawdon Terrace, dating from the time of the 1820s, when the town was a spa destination.

The town has a town council, the lowest level of local government in England. This has 17 councillors, representing six wards: Blackfordby ward (2 councillors), Castle ward (3), Holywell ward (3), Ivanhoe ward (3), Money Hill ward (3) and Willesley ward (3).

The town is in North West Leicestershire district. The district council has 38 wards which each elect one councillor, and these include wards named Ashby Castle, Ashby Holywell, Ashby Ivanhoe, Ashby Money Hill, Ashby Willesley and Ashby Woulds (ie a similar list to the town council wards but including Woulds instead of Blackfordby). It is represented on Leicestershire County Council by one councillor representing the electoral division named Ashby de la Zouch, one of 55 divisions.

The town is in the parliamentary constituency of North West Leicestershire, represented since 2024 by Amanda Hack of the Labour Party.