The interior of the church contains wall paintings dating from the 13th to the early 19th centuries, some of which are illustrated in Professor E. W. Tristram's English Wall Painting of the Fourteenth Century.
Tristram notes that fragments of a reredos survive with paintings of four saints on them, and he also comments on "crosses of rather elaborate design".
Some wall paintings are on crumbling plaster behind painted post-Reformation texts, in places the paint is up to seven layers thick.
There are 15th-century angels above the chancel arch and an early 14th-century Doom on the east wall of the north aisle.
Victorian texts include the Ten commandments, the Apostles' Creed and the Lord's Prayer.
Restoration work on the paintings in 2010 led to access to the church being restricted.

There is a 42-by-24-inch (107 cm × 61 cm) carving of the Mother and Child in the south wall which dates from the time of the Anglo-Saxons.
Until 1910, the carving was on the outside of the church attached to the south wall and used as a sundial.
An incised meridian and other lines were added along with a hole for the gnomon of a scratch dial.
Its original position in the church is not known, but may have been above the altar.

There are also parclose screens between the Carolean-style box pews that date from the Commonwealth era and a hanging pyx.
The font is from the 15th century while the Jacobean pulpit and tester are from around 1630.
There is a Tournai marble slab with a knight in the chancel which dates from around 1300.
The piscina is from the 13th century with a trefoiled head, a shelf and a circular basin.

On the floor of the chancel is a 10-foot (3 m) black marble slab that once held the brass of a 14th-century knight with a basinet, sword and four shields.
The interior of the church contains wall paintings dating from the 13th to the early 19th centuries, some of which are illustrated in Professor E. W. Tristram's English Wall Painting of the Fourteenth Century. Tristram notes that fragments of a reredos survive with paintings of four saints on them, and he also comments on "crosses of rather elaborate design". Some wall paintings are on crumbling plaster behind painted post-Reformation texts, in places the paint is up to seven layers thick. There are 15th-century angels above the chancel arch and an early 14th-century Doom on the east wall of the north aisle. Victorian texts include the Ten commandments, the Apostles' Creed and the Lord's Prayer. Restoration work on the paintings in 2010 led to access to the church being restricted.
There is a 42-by-24-inch (107 cm × 61 cm) carving of the Mother and Child in the south wall which dates from the time of the Anglo-Saxons. Until 1910, the carving was on the outside of the church attached to the south wall and used as a sundial. An incised meridian and other lines were added along with a hole for the gnomon of a scratch dial. Its original position in the church is not known, but may have been above the altar.
There are also parclose screens between the Carolean-style box pews that date from the Commonwealth era and a hanging pyx. The font is from the 15th century while the Jacobean pulpit and tester are from around 1630. There is a Tournai marble slab with a knight in the chancel which dates from around 1300. The piscina is from the 13th century with a trefoiled head, a shelf and a circular basin.
On the floor of the chancel is a 10-foot (3 m) black marble slab that once held the brass of a 14th-century knight with a basinet, sword and four shields.
St John the Baptist Church, Inglesham