In the first half of the twentieth century, American missionary nurses, working under the auspices of the Presbyterian Mission to Iran, established areas of educational innovation within mission medicine and Iranian health care. Drawing on Presbyterian mission records, this article considers missionary nurses’ efforts to cultivate international nursing standards in Iran between 1916, when they opened their first nursing school, and 1947, when they launched an institute of higher education for nurses. From the outset their mission was to develop the nursing profession and “produce fine nurses for Iran.” In effect, they proselytized for the nursing profession. For twenty years they operated the only nursing schools in the country. This article argues that missionary nurses’ commitment to nursing professionalism facilitated Iranian nursing nationalism. It also reveals that some Iranian women took advantage of mission nursing schools to advance their education and cultivate prominent nursing careers.