Mattydale is a hamlet (and census-designated place) in Onondaga County, New York, United States.

Although born in nearby Chittenango, New York, Wizard of Oz author L. Frank Baum spent much of his childhood on the site of Roxboro Road Middle School.

A vacant lot since the Sports-O-Rama skating rink was torn down in 2015, the site previously featured two roadhouses after the Baum family residence.

According to the United States Census Bureau, the community has a total area of 1.9 square miles (4.9 km2), all land.

Mattydale is southwest of Syracuse Hancock International Airport and borders the community of Hinsdale.

Ley Creek, which flows along the south part of Mattydale, enters Onondaga Lake a few miles southwest of the village.