Alciston is a village and civil parish in the Wealden district of East Sussex, England. It is inland, just off the A27 road, about ten miles (16 km) north-west of Eastbourne and seven miles (11 km) east of Lewes. The ecclesiastical parish is linked with that of Selmeston and Berwick.

Saxon in origin, its name was then Aelfsige.

The village (Alcistone) is mentioned in the Domesday Book of 1086, when it was a significant settlement with 70 villagers, 8 smallholders, 12 slaves and 7 burgesses; there were 50 acres of meadows, six of pasture and four of woodland for pigs.

The present 14th-century church, of unknown dedication, is built of chalk from the nearby South Downs.

There is a large medieval tithe barn in the village which is 170 feet (52 m) long and is the largest in Sussex. There is also the ruin of a square shaped dovecote built by monks in the 14th century, who used Alciston as a grange of Battle Abbey.

Every Good Friday, the road outside the Rose Cottage Inn is closed for the villagers to take part in a traditional skipping contest.

The historian C.V. Wedgwood is buried in the church graveyard.

The lowest tier of government for Alciston is a parish meeting. Instead of voting for representatives, a small parish may hold a community meeting twice a year to which all the electors may attend and vote on issues.