Alfriston is a village and civil parish in the Wealden District of East Sussex. The village lies in the valley of the River Cuckmere, about four miles (6 km) north-east of Seaford and south of the main A27 trunk road. The parish had a population of 829 at the 2011 census.

There is strong evidence of ancient occupation of the area, since several Neolithic long barrows have been discovered on the surrounding Downs; among them, to the west is the fairly well preserved Long Burgh.

The place-name 'Alfriston' is first attested in the Domesday Book of 1086, where it appears as Alvricestone, comprising nine households. It appears as Alfrichestuna in a French document circa 1150. The name means 'Ælfric's town or settlement'.

One building of historical importance is the Star Inn. Originally a religious hostel built in 1345 and used to accommodate monks and pilgrims en route from Battle Abbey to the shrine of St Richard, patron saint of Sussex, at Chichester Cathedral, it became an inn in the 16th century. Wooden figures grace the upper part of the building, whilst in the front is a one-time ship's figurehead representing a red lion. The latter is connected with the Alfriston smuggling gang who used the inn as a base; their leader was transported to Australia in 1830. Another important historical building is Dean's Place Hotel which was built in the 17th century or earlier.

An electoral ward in the same name exists. This ward stretches north to Chalvington with Ripe and has a total population taken at the 2011 census of 2,321.

At Westminster, Alfriston has been represented by James MacCleary, Liberal Democrat, Member of Parliament for Lewes since the 2024 general election when he defeated the Conservative incumbent Maria Caulfield.

The Alfriston parish church, dedicated to St Andrew, has Saxon origins, although most of the building dates from the 14th century. It is known, because of its size, as the Cathedral of the South Downs. It sits on a small, flint-walled mound in the middle of "the Tye" (the local village green), overlooking the River Cuckmere, and is surrounded by the flowered graveyard in which the Nobel laureate Sir Peter Medawar and the Labour politician Denis Healey are buried. It is built in the form of a cross. Today it is part of the united benefice which includes St Michael's Church at Litlington and All Saints Church at West Dean. Alfriston's former United Reformed Church is included in that grouping.

The east side of the village lies by the River Cuckmere and is home to the village green, which is called the Tye. In the centre of the Tye is St. Andrew's Church. The 14th-century Alfriston Clergy House close by was originally a farmhouse but later became the vicarage. It is now maintained by the National Trust. It was the very first property bought by the Trust, in 1896, and it is a classic example of a Wealden hall house with thatched roof and timber-framed walls. It also has a tranquil garden and orchard on the banks of the Cuckmere. Also on the Tye is the Georgian Unitarian Chapel. The wooden sign for the village at the entrance to the Tye was carved by a previous vicar of the village who also repaired the Star Inn's red lion. The centre of the village is Market Square which contains a 15th-century market cross.