Police reportedly arrested the gunman who is believed to had worked as a researcher at the institution.
A gunman has shot and killed four teaching staff at a university in Eskisehir in north-western Turkey.
Osmangazi University's head, Hasan Gonen, said in a statement, "Volkan B. first went to the room of the faculty dean, who was not there, and then shot the faculty secretary".
Hurriyet newspaper said three other people were wounded in the attack. A reporter for Anadolu, speaking on CNN Turk, said he had surrendered rather than trying to escape. However the city of Eskisehir, home to almost one million people, has not seen any attacks.
Television footage showed emergency workers at the scene, attending to students and teachers who were in a state of shock.
Turkey's government accuses Gulen, who has lived in self-imposed exile in Pennsylvania since 1999, of having orchestrated the abortive July 2016 attempt by parts of the armed forces to topple President Tayyip Erdogan.
More than 50,000 people have been jailed on suspicions of links to Gulen.
There was no confirmation from authorities on those claims.