Selsey is an English seaside town, about 7 miles (11 kilometres) south of Chichester, West Sussex. Notable residents of Selsey include Patrick Moore.

Selsey lies at the southernmost point of the Manhood Peninsula, a small island almost cut off from mainland Sussex by the sea. There are significant rock formations beneath the sea off both of its coasts, named the Owers rocks and Mixon rocks.

There is one road in and out of the town - which briefly becomes a bridge at a point known as "the ferry", crossing the water inlet at Pagham Harbour (a part of Bognor). The term ferry is used because at the bridge point there was at one time a ferryman who took people across to the island.

Selsey was the capital of the South Saxons kingdom, founded by Ella, who set up his headquarters on the peninsula. Wilfrid arrived circa 680AD and converted the kingdom to Christianity, as recorded by the Venerable Bede. The South Saxon cathedral stood at Selsey until it was moved to nearby Chichester in 1075.

The modern name Selsey is derived from "Seal Island", and until as recently as the 1930s the town's name was variable, also being spelt Selsea.

It's primary economic background until the mid 19th century was fishing trade, however this was equalled in significance by the development of tourism in the town, and during much of the 20th century, visiting holidaymakers (referred to as "grockles" by the locals) doubled the population.

The rise of international travel has led to a slowing of the tourist trade, however still Selsey has a significant leisure industry centred around the many caravan parks in the area.

Selsey has two significant achievements - the B2145 road into the town is the busiest B-road in the UK, and the West Sands Caravan Park is the largest such park in Europe.

The town was the seat of a diocese until 1075, and more recently saw the foundation of the International Bognor Birdman event.

See also: West Sussex Railway.