Keeping Girls in School Act This bill authorizes the U.S. Agency for International Development (USAID) to enter into acquisition, assistance, or financing agreements to address societal, cultural, health, and other barriers that adolescent girls face in accessing quality secondary education. The USAID shall seek to ensure that such activities meet various requirements related to monitoring and evaluating outcomes, collecting data, and adhering to gender-equality promotion policies. The Department of State shall periodically update and report to Congress a publicly available U.S. global strategy to empower adolescent girls. The U.S. Global Strategy to Empower Adolescent Girls, issued in March 2016, may serve as the initial version of the strategy. The USAID shall periodically report to Congress on the activities initiated under this bill and efforts to monitor and evaluate such activities.