The William Penn School District is a large suburban, public school district located in Delaware County, Pennsylvania.

The district serves the boroughs of Aldan, Colwyn, Darby, East Lansdowne, Lansdowne, and Yeadon.

The district encompasses approximately 5 square miles.

According to 2000 local census data, it serves a resident population of 42,457.The district administration offices are located at 100 Green Avenue – Annex Lansdowne, PA 19050.

The district was created in 1972 from the consolidation of three smaller, local districts (Darby-Colwyn, Lansdowne-Aldan, and Yeadon),[2] by state mandate that they merge and desegregate their schools.