International Violence Against Women Act of 2018 This bill provides for a U.S. global strategy to prevent and respond to violence against women and girls. The bill establishes in the Department of State an Office of Global Women's Issues which shall be headed by an Ambassador-at-Large for Global Women's Issues. The Ambassador-at-Large shall: (1) coordinate U.S. government efforts regarding gender equality and the advancement of women and girls in foreign policy, and (2) develop or update periodically a U.S. global strategy to prevent and respond to violence against women and girls. The bill establishes in the U.S. Agency for International Development the position of Senior Coordinator for Gender Equality and Women's Empowerment who shall direct policies, programs, and funding regarding gender equality and women's empowerment. The bill requires that U.S. assistance made available for humanitarian relief, conflict mitigation, and post-conflict reconstruction prevents and responds to violence against women and girls. The Department of State shall also identify incidents that occur during armed conflict and implement emergency responses.