Fleet Marston is a tiny village in Buckinghamshire, England. It is located to the west of Aylesbury, just off the main A41 that leads to Waddesdon.

The village name 'Marston' is Anglo Saxon in origin, and means 'marsh farm'. The prefix 'Fleet' refers to a stream in the parish, and was added to distinguish the village from nearby North Marston. In the Domesday Book of 1086 the village was recorded as Mersetune.

At one time a railway line ran through the parish though this has long since been dismantled. All that remains of the village today is a small number of houses and a farm, and the parish church of St Mary the Virgin.