The oldest parts of St Mary's parish church are 12th-century.
There are records of parish rectors from 1223 onwards.
The baptismal font may be 13th-century and the present chancel arch and north porch were added in the 14th century.
One of the windows is 15th-century.

Parish registers from 1630 onwards survive.
John Wesley is known to have preached his first sermon at Fleet Marston shortly after his ordination as deacon in 1725.
The building was restored in 1868–69 under the direction of George Gilbert Scott.
It is now a Grade II* listed building.
It is also a redundant church in the care of the Churches Conservation Trust.
The oldest parts of St Mary's parish church are 12th-century. There are records of parish rectors from 1223 onwards. The baptismal font may be 13th-century and the present chancel arch and north porch were added in the 14th century. One of the windows is 15th-century.
Parish registers from 1630 onwards survive. John Wesley is known to have preached his first sermon at Fleet Marston shortly after his ordination as deacon in 1725. The building was restored in 1868–69 under the direction of George Gilbert Scott. It is now a Grade II* listed building. It is also a redundant church in the care of the Churches Conservation Trust.
Fleet Marston