Leytonstone (/ˈleɪtənstoʊn/ LAY-tən-stohn) is an area in East London, England, within the London Borough of Waltham Forest. It adjoins Wanstead to the north-east, Forest Gate to the south-east, Stratford to the south-west, Leyton to the west, and Walthamstow to the north-west, and is 7 miles (11 km) north-east of Charing Cross.

Historically, it was part of the ancient parish of Leyton in the Becontree hundred of Essex. The first documented evidence of settlement is from the 14th century, describing a hamlet at 'Leyton-atte-stone'; a reference to the Roman milestone located within the area, that formed a northern boundary of the parish. It remained largely rural until the 19th century, becoming part of the London postal district in 1856, the same year its railway station was opened (now on the Central line). When Greater London was created in 1965, the Municipal Borough of Leyton merged with Chingford and Walthamstow to form the London Borough of Waltham Forest.

At the northern end of Leytonstone High Road is The Green Man, a public house, with an eponymous nearby gyratory road junction system under which the A12 runs. Leytonstone is noted for being the birthplace of Alfred Hitchcock, with a number of references to the filmmaker around the area, including painted murals, mosaics, a pub and a hotel.

The main thoroughfare, Leytonstone High Road, is part of an ancient highway from Epping to London, on the borders of Epping Forest. A small hamlet at Leytonstone had existed since the early 14th century, when it formed part of the parish of Leyton St Mary. The name Leytonstone, originally "Leyton-atte-Stone", comes from nearby Leyton ("settlement (tun) on the River Lea") and the Roman milestone called the High Stone.

The milestone still stands at the junction of Hollybush Hill (the A1199 road with Woodford) and New Wanstead (the A113 road with Woodford Bridge), near the eastern bounds of the parish. It is a restored 18th-century obelisk set up on an earlier stump, traditionally described as a Roman milestone, possibly marking an extension of the Roman road from Dunmow to Chigwell into London. Two of the obelisk inscriptions are still just legible, others not:

Other Roman archaeological features have been found in nearby Leyton, including "a Roman cemetery south of Blind Lane, and massive foundations of some Roman building, with quantities of Roman brick... discovered in the grounds of Leyton Grange."

In 1722, author Daniel Defoe travelled through "Layton-stone, a place by some known, now as much, by the sign of the Green-Man". Leytonstone, along with Stratford, Leyton and Woodford, was one of the villages Defoe called desirable country retreats for wealthy merchants and financiers within an easy ride of the City.

Leytonstone remained largely rural until the opening of the railway at Leytonstone station in 1856, which gave quick and easy access to Stratford and central London. This, with increased availability of office and industrial work, had transformed the area into a suburban dormitory town by the end of the 19th century.