Kings Langley is a historic town and civil parish in Hertfordshire, England, northwest of central London to the south of the Chiltern Hills and now part of the London commuter belt. The village is divided between two local government districts by the River Gade with the larger western portion in the Borough of Dacorum and smaller part, to the east of the river, in Three Rivers District.
It was once the location of Kings Langley Palace, a royal palace of the Plantagenet kings of England. The 12th century parish church of All Saints' houses the tomb of Edmund of Langley (1341–1402), the first Duke of York.
The place-name Langley is first attested here in a Saxon charter of circa 1050, where it appears as Langalega. It is spelt Langelai in the Domesday Book of 1086, and is recorded as Langel' Regis in 1254. The name means 'long wood or clearing'.