Oldland Windmill is an 18th-century post mill situated near the village of Keymer, West Sussex, England.

The Sussex Archaeological Society acquired the mill in 1927 and repairs were carried out by E Hole and Sons of Burgess Hill in 1934.

[3] In 1976, at the Annual General Meeting of the Hassocks Amenity Association, there was a talk was given on the work of Weald and Downland Open Air Museum.

The mill was surveyed in 1977 by millwrights Vincent Pargeter and Edwin Hole and found to be close to collapse.

Following negotiations with the Sussex Archaeological Society in 1979 the Hassocks Amenity Association leased the mill in 1980 and began a period of volunteer-led restoration.

[2] Since then the mill has benefited from a DEFRA grant and substantial work has been completed, almost entirely carried out by volunteers.

The first working party on 2 August 1980 cleared rubbish around the mill and made a temporary repair to the roof of the roundhouse.