The Church of St Mary, standing on the edge of the Park, is known to have existed in 1258, and is well worth a visit. The fine western tower was completed in 1543, and the Tollemache arms appear in many places on it. The plinth has the inscription: scandit ad ethera virgo puerpera virgula jesse (the Virgin Mother, branch of Jesse's stem, ascends to heaven). The south porch is of the same date, but the south doorway is early thirteenth century. It was in 1488 that John Tollemache signed the contract for the building of the tower with the Helmingham church-wardens, and he paid for the tower at a cost of £30.

The church itself is filled with beautiful and magnificent memorials to a number of generations of the Tollemache family, including a large tomb with a verse describing four generations of the family. These were cleaned and renovated in 1976 in memory of John, 4th Lord Tollemache, who had brought Helmingham back to life in the 1950s and who died in 1975. Contributions are gratefully received to ensure the good upkeep of this famous Suffolk church.

When visiting the gardens on a Sunday it is possible to take a public footpath to the church - it is about 500 yards away from the car park.