Church consists of a short, two-stage W tower, nave with a N aisle only, and chancel. Nave arcade of c. 1200; windows N aisle and W window of tower are early 14thc. while the chancel was completely rebuilt in 1854. C. H. Fowler did some restoration work here in 1911. That work may have entailed the Romanesque S doorway, which is heavily restored.

Domesday Book records that the king owned one half the church here and the Bishop of Durham had possession of the other half in 1086. While the Domesday Survey is the first documentary evidence for the church, there is a fragment of an Anglo-Saxon coffin built into the W face of the W tower. Everson and Stocker have suggested that such sculptural evidence may refer to the potentially high status of such church sites in the pre-Conquest period.

Much of this doorway is restored. The crisp voussoirs are clearly new and the lack of bases on the nook-shafts address their resetting here. However the capitals with their continuous imposts and the label, hidden behind the trusses of the porch roof, appear to be good 12thc. material. It should be noted that on the Ordnance Survey map the town name is given as Kirkby la Thorpe; at the church, however, the village name is spelled Kirkby Laythorpe; this most likely derives from the area just S of the village, called Laythorpe, an area which Domesday Book presents as a distinct jurisdiction.