The church consists of nave, chancel, vestry, and tower. The original nave may be 13th century and the chancel 14th century, but parts of the church have been rebuilt at different periods and very little medieval work now remains. In particular subsidence on the south side has necessitated constant repairs. The nave roof may be 15th century. The nave itself is said to have been rebuilt in red brick in 1680. In 1770 the interior of the church was remodelled, including the erection of a west gallery. The nave walls were again largely rebuilt in 1818 and fitted with oak windows. In 1840 the chancel was rebuilt in 14th-century style, and the north tower and porch were added. Unusually, the lowest stage of the tower is both a ringing chamber and the north porch church entrance. The red-brick vestry was built in 1864. In 1902 seven new stone nave windows replaced the wooden windows of 1818. The stone font is 15th century with an octagonal bowl and a moulded shaft. In 1770 the bowl was removed and a new one fitted to the pedestal. In 1936 the original bowl, carved with the initials 'J.P.', was discovered in the churchyard at Little Parndon. It was returned to Bobbingworth and now occupies its original position. There is a 17th century iron-bound chest with two locks inside the church, and the pulpit and reading desk are from the same period.