Alexander is a town in Genesee County, New York, United States.

The town is named after Alexander Rea, an early settler, and is on the southern border of the county.

The next year he laid out a road, now Walnut Street and Route 98, north of the settlement.

The town includes the Alexander Classical School, listed on the National Register of Historic Places.

Tonawanda Creek, a tributary of the Niagara River, flows northward through the town.