The church at Ashton Keynes consists of a nave, chancel, narrow N and S aisles, SE chapel, N and S porches, and a W tower. The nave clerestory and aisles and the W tower were built in the 14thc and the N and south porches were added in the 15thc. However, the church retains many 12thc and 13thc features. The chancel arch, raised and widened in the 1876-7 restoration, retains some stonework from the late 12thc. The W bays of the N nave arcade date from the late 12thc or early 13thc, and the E two bays were added in the first half of the 13thc. The S arcade was built around 1200. The font also dates from the late 12thc.

The manor of Ashton Keynes was held by the Abbot of Cranbourne in 1066 and at the time of Domesday Book. It was then recorded as Essitone, a large settlement of 41 households, located within the Crickland hundred as and valued at £15. No mention of a church in 1086. The church at Ashton Keynes was an appropriated vicarage by 1314.

The regularity of stonework of the capitals in the S arcade makes them appear as if moulded, not carved.