The church, with a rector, existed by 1301 but was completely rebuilt in the mid 15th century and nothing remains of the earlier church. The parish name was originally just Calstone, but by c.1600 it had become known as Calstone Wellington. In 1763 the church was known as St. Mary's and it is likely that this was the original dedication. In the late 18th century a small gallery was built to accommodate the growing congregation. The church was conservatively restored under Ewan Christian in 1884-5. During this work a vestry was built, the chancel reroofed, later narrow windows in the nave and chancel replaced by traceried windows in the 15th century style, and the gallery removed. The top stage of the tower was also rebuilt. There were new oak choir stalls, a prayer desk, a pulpit, a lectern and sittings while the present altar was made from timber from the old chancel roof. The church was re-opened on 10th November 1885. The parish registers from 1760, other than those in current use are held in the Wiltshire and Swindon Record Office.