The educational needs of migrant-background students in primary and secondary schools pose a growing challenge for policymakers and educators around the world. Some national, regional, and local governments have well-designed systems of support for such students, while others are just beginning to establish targeted policies and practices to meet the needs of this growing and diverse population. For policymakers, school funding designs are an important means of influencing how schools and school districts serve their students who are immigrants or the children of immigrants. The rules guiding such funding design usually both reflect and drive the larger goals and priorities of the education system. By providing supplementary funding for high-need groups, such as migrant-background students, policymakers signal that helping these students access the services they need to succeed on par with their peers is a priority. This report focuses on four countries--Canada, France, Germany, and the United States--shedding light on supplementary funding mechanisms targeted to migrant-background students, and some of the key challenges and strategies decisionmakers are wrestling with as they attempt to ensure that additional resources are used effectively. An appendix entitled "Supplementary Funding Mechanisms (Selection)" is included.