The church consists of chancel with S chapel, nave with N and S aisles, S porch and clerestorey, and W tower. The earliest surviving features are the two-bay 12thc. N and S arcades (the S extended later in the middle ages into the chancel to allow better access to the S chapel). A plain 12thc. blocked, round-headed window survives in the W wall of the N aisle. The clerestory is early 15thc. and the tower c.1200. The upper part of the tower and possibly the outer walls of the aisles were rebuilt in the 15thc. The 14thc. chancel was rebuilt in the early 15thc. and substantially restored after a fire in 1969. The S chapel is 14thc. and the S porch is 18thc. 12thc. sculpture is found on the capitals and arches of the N and S arcades. The church is constructed of flint rubble and Totternhoe stone.

VCH records that Abbots Langley was given to St Albans Abbey by Aethelwine the Swart and his wife Wynfleda in the reign of Edward the Confessor.

The Domesday Survey does not mention a church, but states that the manor was held by the Abbot of St Albans. One hide was appropriated by Herbert son of Ivo 'in the time of the Bishop of Bayeux' and was held by the Count of Mortain in 1086. The Domesday Survey also records that there was a priest at Abbots Langley.

The advowson remained in the Abbey's hands until the Dissolution.

The earliest evidence in the church is of the last quarter of the 12thc. Thurlby dates the aisles here and those at nearby Sandridge to the 1180s, viewing both as examples of conservative practice in Hertfordshire architecture.

VCH notes that the stiff-leaf capital of Pier 1 is one of the earliest examples of this type in the county. (VCH, 327)