Unadilla is a town in Otsego County, New York, United States.

Unadilla is located in the southwestern corner of the county, southwest of Oneonta.

The first settlement took place circa 1770 in the area of Sidney (in adjacent Delaware County), followed by Unadilla.

Both Sidney and Unadilla were destroyed during the American Revolution and were re-established after the war.

The Unadilla Waterworks, Russ-Johnsen Site, and Andrew Mann Inn are listed on the National Register of Historic Places.

23.6% of all households were made up of individuals, and 10.1% had someone living alone who was 65 years of age or older.