This thesis sketches out the history of Ottoman-Arab emigration from Greater Syria to the United States and to Argentina from the late nineteenth century up to the end of World War I, relying primarily (but not solely) on the related documents preserved in the Ottoman Archives. It depicts a wide range of this emigration history, including the scale and the number of immigrants, the causes behind emigration, the ways that emigrants managed to reach the Americas, the attitudes of Ottoman governments toward them, and the ways that emigrants adapted to their host societies. The thesis analyses the Ottoman-Arab emigration phenomenon from social and economic perspectives and in the larger context comprising other European population movements to the New World during this period, which has been called 'the Age of Mass Migrations'.