In 2004, the United States Agency for International Development (USAID)-funded Educational Quality Improvement Program 2 (EQUIP2) began investigating community-based schools as a mechanism for reaching the underserved populations. The team identified nine models that successfully organized schooling in regions least served by the formal education system. These complementary education approaches rely on community, non-governmental, and ministry collaboration and present a promising response to the challenge of meeting the EFA goals of universal access, completion, and learning. Complementary Education models work in support of the formal public system, offering students an alternative route to achieving the same educational outcomes as students in the government schools. The programs are designed to feed students into the government system at various entry points and are large enough to exhibit many of the same characteristics as mainstream schools. Over time, the models have increased rates of attendance, completion, and learning among the populations they serve. This EQUIP2 working paper synthesizes the findings from the nine case studies of successful complementary education programs in Afghanistan, Bangladesh, Egypt, Ghana, Guatemala, Honduras, Mali, and Zambia. The research demonstrated that the programs are more cost-effective than government schools in delivering education services and that they achieve higher learning outcomes through adjustments in school size and location, curriculum and language of instruction, school management and governance arrangements, and teaching staff and instructional support services.