This study of Ottoman Greek immigrant racial classifications and identities in the early twentieth-century United States is partly based on analysis of a systematically collected random sample of 1,283 ship manifest files for immigrants who arrived in the United States between 1900 and 1930 through Ellis Island (Ellis Island Online Archive) from regions that were part of the Ottoman Empire or (after 1923) the Republic of Turkey. About 48 percent of these immigrants, the largest cohort, racially self-classified as “Turkish Greek,” “Greek Greek,” or “Ottoman Greek.” Approximately 20.5 percent identified as Armenian and the remainder used other national or racial categories. The paper shows how relevant US immigration laws in the early decades of the twentieth century shaped the racial identities and self-categorizations of the Ottoman Greek immigrants. Documents analyzed include the Dictionary of Races and Peoples, which was published as part of the US Congress’s Joint 41-volume Dillingham Commission Report on immigration in 1911 and formalized racial identity categories for US immigrants. The random sample of Ellis Island files analyzed indicates that the majority of Ottoman or Turkish immigrants between 1900 and 1930 were male (70 percent) and single (61 percent) and largely came from the Marmara region. Approximately 38 percent were between 21 and 30 years old, 28 percent were 20 years or younger, and 15 percent were between 31 and 40 years old. The largest proportion arrived at Ellis Island between 1919 and 1922 (37 percent). I found that the anti-immigrant Dillingham Commission’s classification system compelled Ottoman Greek immigrants to use the racial categories of US immigration authorities. When Ottomanism was mainstream (1909-1913), a substantial proportion of the total sample (3.3 percent) identified as Ottoman Greek. Between 1919 and 1922 (during the period of the Greek suzerain), most immigrants shifted from claiming “Turkish Greek” to “Greek Greek” identity. In a broader sense, these findings indicate that geopolitical events and immigrant identity as codified by the US government, resulted in the racialization of this immigrant group as white.