Greenfield is a town in Saratoga County, New York, United States.

It is located northwest of Saratoga Springs, and is the largest by area in the county.

The area was first settled circa 1786, and in 1793, the town was formed from parts of the Milton and Saratoga.

Its land area was reduced in 1794 by contributions of some of its territory to the newly formed towns of Day, Corinth, and Hadley.

20.4% of all households were made up of individuals, and 7.4% had someone living alone who was 65 years of age or older.