This study examines the ways by which Hadramis played pivotal roles in the economic, political, religious, urban and intellectual history of Eritrea in the nineteenth and twentieth centuries. Hadrami commercial entrepreneurs and laborers moved and settled in Eritrea and prospered under Egyptian (1865–1885) and Italian rule (1885–1941) in import-export, wholesale, retail, urban construction, real-estate, transportation, light-industrial and agricultural enterprises and businesses. They also played central roles as leaders in municipal and commercial institutions, and generously supported the establishment and running of mosques and Islamic educational institutions. Hadramis also contributed to shape the Eritrean political sphere, where as some of the foremost leaders of the Muslim League, activists of Hadrami origins articulated political discourses that were influenced by Islamic modernist thought, global nationalist trends as well as ideologies concerned with social reform, education and ‘progress’. Yet by the middle of the twentieth century sectarian nationalist politics, the stricter control of international currency flows, and the curbing of movement across new national borders heavily affected Hadramis and their networks throughout the Indian Ocean. In Eritrea, growing anti-Arab campaigns between the 1940s and 1960s and the nationalization and confiscation of their properties in the 1970s led many Hadramis to leave the country and seek their fortunes elsewhere.