St Mary's has an aisled and clerestoreyed nave with three-bay arcades. Of these bay 1 of the S arcade is 13thc. and may, according to Pevsner, have been a transept arch originally. The rest of the S arcade and the entire N arcade are either 19thc. in their entirety or heavily restored work of the years around 1300. The clerestorey windows are 14thc. The S aisle has been extended E alongside the chancel to form a chapel, now in use as an organ loft and vestry. The chancel also belongs to c.1300. At the E end the lowest part of a tower remains, including a 14thc. window. The spire had fallen in 1703, and most of the remainder was demolished in 1967. In its place a bellcote was built on top of the west gable. A date stone of 1601 over the S doorway presumably records a restoration. The church is of ironstone and grey stone in roughly-coursed blocks. The only Romanesque feature is the elaborate late 12thc. S doorway.

Formerly a dependent chapel of Great Harrowden,now a parish church. The earliest reference to the chapel is in Bishop Hugh II's act of 1227.

Benefice of Great Harrowden with Little Harrowden and Orlingbury.

RCHME suggests that that doorway originally stood in the S wall of an aisleless nave. The crocket capitals and multiple mouldings including keeled profiles points to a date of c.1190-1200. The elaborate arrangement of stepped embrasures on straight slanting socles is an unusual one in this country, and did not become common in France until after 1200 (Baxter 2000). It presumably belongs to the resetting rather than the original design, as at Bourges.