The internal spreadsheet included names, birthdates, addresses and parents' names for the approximately 2,700 students in the Fleetwood school system.
Superintendent Paul Eaken said Wednesday that a parent notified school officials after seeing the information published on Wikispaces.
Eaken says the district contacted police, and the data was later removed from the website.
An email to parents from Eaken says district officials are working with police to find out how the breach occurred.
Fleetwood is about 50 miles northwest of Philadelphia.