ABSTRACT The last decades of the Ottoman Empire were characterised by mass violence that saw millions, mostly Ottoman Christians, perishing and forcibly moved within Ottoman borders, or expelled out. While it is generally accepted (except by Turkey and pro-Turkish commentators) that what befell the Armenians in 1915 and 1916 was a Genocide, in recent years many have taken to calling what befell other Ottoman Christians as a genocide as well, referring to a genocide of Armenians, Greeks and Assyrians from 1915 to 1923, and some even to a 30-year genocide. This essay attempts to scrutinise this recent trend, by contrasting what happened to the Armenians and the Greeks during the last years of the Ottoman Empire and during the rise of Nationalist Turkey, namely from 1915 to 1923. It first distinguishes between the terms genocide, genocidal and ethnic cleansing. It then establishes that population numbers are pivotal to genocide, as those killed and those that survived are important to evidence intent and application. The article then delves into the cases, comparing and contrasting across the criteria of intent and destruction processes, and the number of dead and survived. Finally, the article answers why the Armenian case (1915–16) is a Genocide, but not the Greek case (1915–23) or that of the Armenian case (1919–23). This article is important for the overall special issue on mass deportation because it clarifies the differences between various genocidal processes, including mass deportation, ethnic cleansing, and genocide.