St Mary's is a flint church with a single, thatched nave and chancel, no chancel arch and a tall 14thc. W tower with diagonal buttresses and flushwork on the parapet. The two nave doorways are 12thc. work; the S protected by a 14thc. porch.

In 1086 Henstead was a berewick of Wrentham, held by Godfrey de Point from William de Warenne. The same family, later called Pierpoint, remained in possession of the manor until the early 14thc., when they moved to Hurstpierpoint, Sussex. The manor of Henstead passed to the family of St Denis around this time.

Sole Bay Team Ministry: i.e. Blythburgh, Covehithe with Benacre, Frostenden, Henstead with Hulver, Reydon, Sotherton, S Cove, Swold, Uggeshall, Walberswick, Wangford and Wrentham.

Chamfered block capitals as on the N doorway also occur at Ilketshall St Andrew, where chevron of the same profile as on the S doorway also appears. The multi-billet label of the S doorway is a common feature locally, found in various forms, e.g. at Whall and Wissett.