Middleton-on-Sea is a village, civil parish and an electoral ward in the Arun District of West Sussex, England, lying to the east of Bognor Regis and neighbouring Felpham.

In the 2001 census, 5,105 people lived in 2,366 households, of whom 2,206 were economically active, a lower than average proportion but higher than other coastal resorts.

Two larger houses were built during the same period: Middleton Field west of Yapton Road, home of the owner of the adjacent brickworks, and the half-timbered and pebbledashed Ancton Lodge.

The firm was later called the Norman Thompson Flight Co. During the First World War it supplied aircraft to the navy, the workforce growing from ten at the beginning to between 700 and 900.

The New City had its own dairy, farm, ice generating plant, and mineral water factory, besides a laundry, hairdressing rooms, and lending library.

While there had been a church at Middleton in 1086, by the late 18th century most of the chancel had been destroyed by the sea, the south aisle demolished and its arcade filled in, and part of the west end including the tower removed.

The erosion of the churchyard inspired the poet Charlotte Smith to write a sonnet "Written in the Church-Yard at Middleton in Sussex" (1789).

A very high tide early in 1838 virtually destroyed what was left of the building, rendering it unusable; the ruins survived in 1847 but had disappeared by c. 1849.

Of flint with stone dressings and some brick and in 13th-century style, the building was consecrated in 1849 on a site given by Richard Coote, lord of Middleton manor.