Hadlow is made up of the Saxon words 'haeth' meaning 'heather' and 'hlaw', representing 'hill mound', resulting in the 'hill growing with heather'. The first recording was in the Domesday Book when written as Haslow, other spellings include Haselholte and Hadloe.
The church is dedicated to St. Mary, and was first mentioned in 975, when only a wooden Saxon building. This appears to have been rebuilt of stone in1018, when Hadlow was given to Queen Eddeva the consort of Edward the Confessor. After 1066, the land was given to Richard de Clare, who in turn granted it to the Knights Hospitallers of St John of Jerusalem based at nearby West Peckham, in 1166. The Knights held the land until Henry VIII dissolved the order and the Monasteries in 1536 - 37
The church tower probably pre-dates 1018, although was added to in the 13th Century. A large bell appears to have been present in the 16th Century. The main doors were replaced in 1636. A clock, by John Thwaites of Clerkenwell, was added in 1791.At the beginning of the 19th Century the church was in a poor condition, although considerable repairs were carried out during the century. In 1847, the chancel was rebuilt and the vestry added. In 1853, the south aisle was blocked up and the north aisle built and the then owner of Hadlow Castle installed a private gallery at the west end with its own access. In 1936, the church and roof were again restored and at the same time, the gallery was removed.
