East Horsley is a village and civil parish in Surrey, England, 21 miles southwest of London, on the A246 between Leatherhead and Guildford. Horsley and Effingham Junction railway stations are on the New Guildford line to London Waterloo. The two-halves of ancient Horsley are similar in having substantial woodland and some chalky lower slopes, in the south, of the North Downs.

East Horsley appears in Domesday Book of 1086 as having two manors, listed under the chief manor's heading of Horslei. This was held by Lanfranc, Archbishop of Canterbury. Its domesday assets were: 3 hides and 1½ virgates; 8½ ploughs, woodland worth 50 hogs. It rendered £5 per year to its overlords.

The Bishop's Manor in East Horsley seems to have belonged to the see of Exeter throughout the Middle Ages. Malden writing in 1911 associates closely the Domesday entry in Latin meaning 'Bishop Osborn of Exeter holds Woking' with this manor which his successors later held, since there is no trace of any land held by the Bishop of Exeter in Woking in pipe rolls, Assize Rolls, feet of fines or the records of Lambeth Palace.

In 1792 an Inclosure Act enabled William Currie MP to inclose most of Horsley Common at the northern end of the parish and the common fields and waste at the southern part, very much on the chalk. The parsonage and glebe were at the same time moved within the parish.

The village is the site of Horsley Towers, a gothic mansion designed by Sir Charles Barry (later the architect of the Houses of Parliament) for William Currie in place of an earlier building. Currie, a distiller and banker, had bought the property in 1784 and over the next 44 years made extensive changes to the village, including rebuilding most of its houses, establishing the school and restoring the church.

After Currie's death in 1829, the property was acquired by the 1st Earl of Lovelace. It was the marital home of Ada, Lady Lovelace (the writer, mathematician and world's first computer programmer) and later Sir Thomas Sopwith, aviation pioneer.

In 1971 it was used as a (Defence) Staff Training College and was placed in the second category of the English Heritage scheme of architecture as a Grade II* listed building. The buildings were used as a location for the film, The Colour of Magic, in 2008. It is currently in use as a hotel.

William King, 1st Earl of Lovelace (1805-1893) constructed fifteen bridges, known as the Lovelace Bridges, on his estate to facilitate the transport of timber by horse-drawn carts. The bridges were built where the tracks crossed existing bridleways or roads. Ten bridges still exist.

The 3rd Earl of Lovelace imposed restrictive covenants on most of his former fields when selling these to private developers in the early 20th century, leading to the overwhelming proportion of homes being detached; no minimum plot size is specified by these, and planning is controlled by Guildford Borough Council, subject to advice from the civil parish council.