The late 12thc. W tower was rebuilt in 1950 after bomb damage, and vestries were added to either side. The nave and aisles were rebuilt in 1835, following a fire, but the chancel is medieval. The vestry and organ chamber on the S side of the chancel date from 1893, at which time the medieval S arcade was reopened.

Neither church nor village is mentioned in the Domesday Book, but as two churches are mentioned under Kingston, it is assumed that one would have been Southwick. It was probably a dependency of Kingston church at that date. Between 1173 and 1189 it was granted to the Knights Templar.

The church suffered from a fire in the early 19thc., and the nave and aisles were rebuilt in 1835 (by John Garratt). In 1893 the present vestry and organ chamber were built on the S side of the chancel, and the blocked S arcade was reopened. Harrison recorded that the church had been restored and enlarged several times (1875, 1888 and 1893).

The tower was damaged by an unexploded bomb in 1941, and undermined by subsequent excavations made to locate the bomb. As a result, it had to be dismantled. The stones and timbers were numbered and stored until the tower was rebuilt (by J L Denman), together with flanking vestries, in 1949-50. A W doorway was provided where there had not previously been one.

In 1520 the medieval dedication may have been to St Margaret (VCH vol. 6 pt 1, 180-82),

Although the lower stage of the tower is supposedly Saxon or '11thc.', it appears to have dated from the third quarter of the 12thc. It would have been built against the W wall of the nave, masking the W doorway of c.1100. The upper parts of the tower date from the early 13thc.

Although the shaft of the central column of the S chancel arcade looks original, the capital looks Victorian. The stone has the same finish and colour as that on the rere-arch of the W doorway. Both probably date from the 1835 rebuilding, which followed a fire.

The plain square font is probably 13thc. in date.