Philliou specializes in the political and social history of the Ottoman Empire, particularly in the 18th and 19th centuries. Her forthcoming book, Biography of an Empire: Governing Ottomans in an Age of Revolution (University of California Press, Fall 2010) examines the changes in Ottoman governance leading up to the Tanzimat reforms of the mid-nineteenth century, using the vantage point of Phanariots, an Orthodox Christian elite that was intimately involved in the day-to-day work of governance even though structurally excluded from the Ottoman state. She has also written on the Ottoman legacy in the Middle East and Balkans today.