Gregorian earned his PhD in International Relations and Strategic Studies from the Johns Hopkins University School of Advanced International Studies in 1998, an MA in War Studies from King’s College, University of London in 1989, and a BA with Honours from the University of Pennsylvania in 1986.
Gregorijan je doktorirao Međunarodne odnose i strateške studije na Školi za napredne međunarodne studije Univerziteta Džon Hopkins 1998, magistrirao Ratne studije na Kraljevom koledžu Univerziteta u Londonu 1989 i diplomirao sa počastima na Univerzitetu Pensilvanija 1986.