Chailey is a village and civil parish in the Lewes District of East Sussex, England. It is located 7 miles north of Lewes, on the A272 road from Winchester to Canterbury. The Prime Meridian passes just to the east of Chailey.

The parish consists of the settlements: South Chailey (which also incorporates South Common), South Street, Chailey (also known as Chailey Green) and North Chailey (which incorporates the North Common).

The parish church is dedicated to St. Peter and is recorded as having been built in 1256. Recently a special service was held to commemorate its 750 years. At one time Chailey had more churches than pubs. The churches being St Peter's, St Martin's (within Chailey Heritage), Chailey Free Church, St John's (now housing in South Common), and St Mary's (now housing in North Common), and the pubs being the King's Head, Five Bells, Horns Lodge and the Swan House. In addition it is believed another chapel was sited near the Bluebell railway.

Chailey is reputed to be the inspiration for the 1969 children's television series Chigley by Gordon Murray, (along with nearby Plumpton as Trumpton and Wivelsfield Green as Camberwick Green).

The parish of Chailey is large. It is so special because it is one of the remaining areas of the Sussex Weald with heathland Commons. Chailey Common is a Site of Special Scientific Interest that is located within the parish. It also has many areas with ancient woodland. To the north are the parishes of Haywards Heath and Fletching, to its east are Newick and Barcombe. To its south it borders the parishes of Hamsey, St John Without and East Chiltington and to its west, Wivelsfield.

The parish has a 13th-century church dedicated to St. Peter at Chailey Green (TQ 392 193). The large graveyard has two fine old Yews that are over three span girth. The little archaic grassland is unimproved and a Site of Nature Conservation Interest (SCNI), but the parts nearest the church are mown too often and the southern extension are in poor condition. It is worth recording that at least one part of the SNCI (TQ380 189), a relict wet meadow, just north west of The Hooke has been destroyed only recently (2017).

The Heritage Mill is situated on the Red House Common. It is also known as Beard's Mill. It stands beside a yew tree said to mark the centre of Sussex. Records show that mills have stood here since at least 1590. The mill museum is open to visitors regularly.

There used to be a mill on the South Common in South Chailey, opposite where Chailey School is situated, but it has worn away over time.