"Genocide in Kurdistan" most often refers to events that are recognized as having occurred in Iraq during the late 1980s and early 1990s. Scholars also connect it with events in Turkey's early years as a republic. This article describes how some scholars' expansive conception of Kurdistan encompasses regions that also witnessed genocides as large as or larger (in quantitative terms) than these two cases. Armenians, Assyrians, Yezidis, Mandaeans, Shi'i Arabs, and Greek Orthodox Christians witnessed extermination campaigns at various points in Ottoman, Persian, Iraqi, and Turkish history. What is remarkable about Upper Mesopotamia is that these genocides may have reduced native populations in absolute numbers, as compared with ancient or early medieval figures, and to a greater extent than after the genocides of the Kurds or other groups. Like the work of Raphael Lemkin, this article's analysis will not be limited to the period since the Genocide Convention entered into force. Instead, it presents evidence of continuities between the denationalization strategies, official pretexts, and regions mentioned in histories of the various genocides in Upper Mesopotamia.