Winchester city walls are a series of defensive walls in central Winchester, originally built during the Roman settlement of southern Britain, in what was then the settlement of Venta Belgarum.

The area surrounding Winchester had been populated throughout the Iron Age, with Britonnic settlements existing at Oram's Arbour, St Catherine's Hill, and Worthy Down; Venta Belgarum took its name from the Belgae tribes of the area.

Earthwork defences were constructed around the end of the second century, being rebuilt in stone during the latter part of the third century..[1][2] Under Saxon rule, Alfred the Great rebuilt Winchester and its defences as part of the burh system developed to protect against Norse incursions.

[3] As well as the royal castle in the West of the city, Wolvesey Castle, the palace of the Bishop of Winchester, was built in the East of the City alongside the River Itchen; during the Civil War known as The Anarchy, the forces of Queen Matilda, on behalf of King Stephen, besieged the forces of Empress Matilda, destroying much of the old city including the urban defences, in an event known as the Rout of Winchester.

In the English Civil War, the city was seized on behalf of the King by royalist Sir William Ogle, before being captured by Parliamentary forces led by Sir William Waller; the city was subsequently recovered by the Royalist forces before being recaptured by Parliament after the Battle of Cheriton, after which much of the castle was demolished, apart from the Great Hall.