St Mary's Church is an Anglican church in the village of Walberton in the district of Arun, one of seven local government districts in the English county of West Sussex. Its 11th-century origins are now mostly hidden behind the results of extensive restoration work undertaken since the 18th century; but some Saxon-era fragments remain, and reused Roman building materials can still be seen in the walls. The extensive collection of 18th-century gravestones in the churchyard includes some especially macabre examples. The church is protected as a Grade I Listed building.