The C12 nave and chancel are built in one and are rendered externally.
The C12 origin of the building is apparent, however, in the pair of C12 windows flanking the E window.
The S tower porch is of uncertain medieval date.
The N aisle was added in 1881 and has pairs of uncusped Tudor-style windows and a shouldered NW door.
Squared stone masonry in the lower part of the aisle wall is probably reused and may be C12.
The E wall has two large, plain early C12 blind arches, and above them the C12 windows are deeply splayed.
The four-bay N arcade of 1881 is in a C13 style and has polygonal piers with moulded capitals.
C19 polygonal stone font.
C19 timber drum pulpit with blind tracery panels on a wineglass stem.
HISTORY The present church is early C12 in origin, and although small, clearly had a degree of architectural pretension with blind arches on the E wall that must originally have flanked a niche for an altar.
The early date of the fabric is something of a puzzle, however, as the documentary evidence suggests that the church was founded in the mid C13
as the document is of c.1350 and therefore is a later retelling of the foundation, it is possible that its dating evidence is confused.
At that time, early watercolours show that the roof was steeply pitched, and that the church had small C12 lancets in the S wall, a small S porch, and two possibly C12 windows in the W wall.
REASONS FOR DESIGNATION The church of St Katherine, Knockholt, Sevenoaks, is designated at Grade II* for the following principal reasons: * Parish church, with early C12 nave and chancel in one. * Early C12 E windows and internal blind recesses in E wall. * Tower of uncertain medieval date, partly rebuilt c.1840. * Church refenestrated in the early C19, N aisle 1881 by A R Stenning. * Pre-Reformation bell frame survives in part.