My project explores the unconventional participation of Ottoman socialists in Ottomanism, which was a branch of imperial nationalism, and discusses the ways in which separatist nationalism, in its heyday, was challenged by socialist internationalism in the Ottoman Empire during the first term of the Second Constitutional Era (1908-1912). Following the activities of these left-wing intellectuals, combatants and workers, from the predominant ethnic groups (Greek, Jewish, Macedo-Bulgarian and Turkish) in the Balkans and Anatolia in an age when the national question was inescapable, I focus on their joint pursuit of this imperial project which sought both the socio-political equality of all residents of the realm, irrespective of their ethno-religious origins, and imperial unity. It is this distinct composition of a political movement which seldom appears in the studies of either Ottoman Empire or socialism which constitutes the main focus of my dissertation. Benefiting from a variety of un(der)studied materials, this project has two goals: (1) to analyze the unconventional reconciliation of socialism with Ottomanism (2) to reconsider the influence of these two movements in the Ottoman Empire. Moving away from the teleological approaches to pan-ethnic nationalism and proletarian struggle in the Ottoman studies, which condemned both movements to the failure paradigm, I hope to shed light on Ottomanist socialism and its achievements in promoting class identity and the territorial integrity of the Ottoman Empire.