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Coordinates: 50°44′06″N 0°47′23″W / 50.73502°N 0.78977°W / 50.73502; -0.78977 Selsey Abbey was an abbey at Selsey, Sussex, England. It was founded in 681, and became the seat of the Sussex bishopric, later moved to Chichester.

Its founder abbot was Wilfrid of York after his expulsion from the bishopric of York in 681. He founded it on lands granted to him by the local king, Æðelwealh, in gratitude for his exertions in relieving a famine in Sussex. These lands are now probably submerged by the sea off the Sussex coast near Selsey. Wilfrid's successor as Abbot was Hedda (686-705).

Hedda was succeeded by Eadberht, who became the first formal Bishop of Selsey, taking the abbey as his cathedra. So it remained until the see was moved to Chichester Cathedral in 1075 under William the Conqueror then the abbey declined and was abandoned.