Woodlyn is a census-designated place (CDP) in Delaware County, Pennsylvania, United States.

It is bordered to the northeast by the Folsom part of Ridley Township, to the east by the borough of Ridley Park, to the south by the borough of Eddystone, to the southwest by the city of Chester, to the west by Nether Providence Township, and to the north by Springfield Township and the borough of Swarthmore.

Center City, Philadelphia, is 14 miles (23 km) to the northeast via I-95.

According to the United States Census Bureau, the Woodlyn CDP has a total area of 1.7 square miles (4.3 km2), all land.

There were 4,132 housing units at an average density of 2,511.8 per square mile (969.8/km2).