It is a typical parish church with a sturdy square tower at the west end with battlements and tall crocketed pinnacles at the corners. There are more crocketed pinnacles on the south aisle, which also has stone carved gargoyles. The fabric in the nave dates from the 13th century whilst the big square windows were added later. The tower fell down in the mid 18th century and was rebuilt. It contains a ring of six bells. The Vicar, Henry Vincent Bailey funded a major restoration of the church in 1818 when the chancel and south wall were rebuilt. An ornate pulpit and font were placed in the middle of the chancel but these were later removed. He also acquired a lot of medieval stained glass from neighbouring churches. The east window is wholly constructed from a mixture of these reset pieces. There is also a north western window, and several window traceries containing old glass. There are also 19th century windows by Burlison and Grylls. It is said that as a result, Messingham church probably has more stained glass than any other church in Lincolnshire. On the west side of the south porch is a large piece of reused masonry which some people believe could be from a Roman building. Inside, the church is large with arcades of round and octagonal pillars and pointed arches separating the nave and side aisles. There is a small window at the top of the chancel arch with Christ crucified with an angel on either side. The small round topped door into the tower is thought to be part of the original Norman church. This leads into the ringing chamber with a wooden ladder giving access to a trap door leading to the bells. On the walls are boards recording details of peel rung in the 1980s. The current organ dates from 1976 and was taken from a redundant Methodist Chapel in South Yorkshire.