The church of St. Mary consists of a nave with clerestory, N and S aisles, chancel, vestry, S chapel, S porch and a W tower. It is primarily of the 13^th and 14^th centuries. The chancel, S aisle and S porch are of the 13^th century; however, the chancel took on its present dimensions during further work in the 14^th century when the N aisle, clerestory, W tower and broach spire were also added. The date of what may be a S chapel at the E end of the S aisle is unclear due to extensive rebuilding. The S porch was rebuilt in 1673 and the vestry was added in 1858. During a major restoration in 1897, which included the S aisle, clerestory and spire, fragments of the earlier church were discovered, including two pieces of Anglo-Saxon interlace work. Additionally, part of a Romanesque tympanum and several other decorative fragments were found; all of these are now reset into the W wall of the S aisle. The font also dates from the Romanesque period.

Greetham is mentioned in Domesday Book as held by the king, William I, but there is no reference made to a church here in 1086. In 1090, William II gave the manor of Greetham, along with that of Cottesmore, to the Beaumont/Newburgh family as part of the earldom of Warwick. Waleran of Beaumont became the 4^th Earl of Warwick in 1184, and sometime before his death in 1204 he granted the vill of Greetham, along with the advowson of the church, to his younger son, also named Waleran. This may be the earliest mention of a church here. The grant was confirmed by King John in 1208. Before 1235 the advowson was granted to the Priory of St. Sepulchre in Warwick and a vicar, vicarage and fixed stipend were provided for the church. The advowson remained in possession of the Priory of St. Sepulchre until the Dissolution.

All three reset billet fragments in the S aisle, W wall have a small roll mold at the edge so they may have all been from one piece originally. The two lengths of reset imposts, with their hollow chamfer and quirk on face profile, resemble the 13^th c. imposts of the S arcade which was rebuilt in 1897.

On the font, the upper NW corner is a replacement, including the top part of the head crocket, hence the greater amount of plasticity in the carving technique on this head crocket compared to the other three. On the N side, the W half of the impost area and the four western-most bits of dogtooth below it are all renewed. On the S side of the font, the center of the impost area and the dogtooth band are also new inserts and the lower part of this side has a large, repaired crack.