All Saints' has a five-bay nave with a wide N aisle; a chancel with a N chapel continuous with the nave aisle, and a N vestry; and a five-storey W tower with a spire. The building history is a complex one. The three W bays of the nave arcade date from c.1180. In the 13thc., nave and aisle were extended E by two bays, then in the 14thc. the chancel was extended E, the aisle widened, and the N vestry built. At the same time the S nave wall was rebuilt and the porch added. In the 15thc. a W tower was added, built partly inside the W bay of the nave. The chancel arch was rebuilt c.1500, and a clerestorey added to the nave. There was a restoration in the 19thc. involving the rebuilding of the S wall and nave clerestorey. The chancel is of ashlar, the nave and aisle of roughly-shaped blocks of stone decorated with rows of pebbles, and the five-storey tower of rough ashlar blocks. Apart from the N arcade, Tilbrook is notable for a 12thc. relief set in the S porch gable, and a loose window head and sections of an important cross-shaft, at present inside the S porch.

The manor of 5 hides was held by William de Warenne in 1086, but a counter claim was made by Hugh de Beauchamp.

Pevsner describes the relief (III.3.d) as a man with a pig, suggesting a 12thc. date. RCHM(E) Inventory suggests a figure with a whip, beating the animal. Another possibility is a Good Shepherd, although the figure looks like a farmer rather than Christ. The cross is noted by Pevsner as 12thc., 'probably not from Tilbrook', but not by RCHM(E). 12thc. carved stone crosses like this one are not common in this part of the country. Other reasonably local examples are the cross-head at Rothersthorpe (Northants), and the shafts at Harmston (Lincs) and Castle Hedingham (Essex), but none is particularly close to this one.