The church is built of flint and rubble with tiled roofs. A 12th Century nave, with fine Norman chancel arch with zig-zag moulding leads into a mainly 13th Century chancel.

Entrance to the church is by the West door, down a short flight of steps. There is also a South porch, now used as a vestry. On the North side of the chancel is a small chamber housing the organ; This was built by Hele of Plymouth and given in 1922.

Of the treasures of the church the glass is of particular interest Pevsner says: 'In the chancel more of 15th Century glass than in any other Hampshire village church. In the E window the larger lower figures are largely the work of the restorer, but the small figures in the tracery heads are almost intact Fragments (of mediaeval glass) in the chancel side windows.' It is thought that parts of the glass in the E window came from the Holy Ghost chapel at Basingstoke. If so, it is probably similar to the glass in the chapel of The Vyne, both being commissioned by Lord Sandys and carried out by flemish workmen in 1524. Parts of the glass from the Holy Ghost Chapel were kept at The Vyne in the 19th Century, and may have been inserted into the windows here when it was restored about 1890 in memory of Sir John Barker Mill. There is a tradition that during the Civil War the Vyne glass was hidden for safety in a lake. This may be the source of the legend that the glass now in Mottisfonfs East window was once hidden in the River Test

There is another sign of the connection between the Vyne and Mottisfont in the chancel floor, a small brass to William Sandys 1628.

On the South wall of the chancel is a large 16th Century monument with the figures of a man, his wife, two sons and two daughters. Unfortunately the monument has been badly treated and damaged and the inscription has been lost It is, however, dated 1584.

In the nave are a piscina, two tomb recesses, and three 14th Century windows. One window is filled with glass in memory of Mrs. Humbert; the other two form memorials to the Meinertzhagen family.

There is also an unusual memorial near the South door, a tablet with a stone carving above, to Daniel Meinertzhagen, born 1875, died 1898. The carved stone was brought from the chapel of St Michael, Bremen, which had been built in 1693 by Daniel Meinertzhagen and Bruno Heelman, Senators of the Free Town of Bremen.

The South door has a plain rounded Norman arch. The West door is 14th Century, with a 15th Century window above it Traces of an earlier window may be seen in the first stage of the bell turret

The bowl of the font is of Purbeck marble, on a modern plinth.

Of the furnishings of the church the pews, for 120 seatings, were provided at the restoration in 1876, when the old pews and gallery were removed. The reredos and pulpit were given in 1913.

There are five bells in the bell turret These were rehung in 1890 on a wooden frame with wood headstocks.

A rare 17th Century clock movement from the tower was restored to working order, in 1988.