The 4-1 decision dated Wednesday and released Thursday upholds a lower court ruling that sided with Jennifer Henn and her former employer, the Times-Tribune of Scranton.
Two former Lackawanna County commissioners sued Henn and the paper over a January 2004 story that said they were not cooperative in their appearances before the grand jury.
The Supreme Court said reporters cannot be forced to identify confidential sources — a protection granted by the state's Shield Law.
Grand jury proceedings are secret and state law bars prosecutors, court officials or jurors from discussing such investigations. Witnesses are not barred from discussing their testimony outside the courtroom.
Lackawanna County Judge Robert A. Mazzoni had ruled that the importance of grand jury secrecy outweighed the protections of the Shield Law, but a three-judge Superior Court panel determined that Mazzoni had carved out an improper exception to the law. The high court agreed with the panel.