The greatest barrier to achieving the Millennium Development and Education for All goal of universal, quality primary education by 2015 is the inability of public education systems in the poorest countries to adequately reach and educate large segments of their populations .Not only are significant numbers of children underserved in terms of access to education, the public schooling that is provided fails to provide most who do attend with basic literacy and life skills. This failure has enormous consequences for national education systems, for countries’ human resources and economic development. However, complementary models for providing primary schooling, typically provided through NGOs, have been able to reach and effectively educate these under-served areas and populations, often doing so far more effectively than the formal public system. Yet there are few countries that have developed policies and partnerships within national education sector programs to build on the experience and insights that complementary models provide. This paper reports ongoing research that explores how it is that complementary education models organize and deliver primary schooling that assures children’s learning, and examines policy implications for achieving quality basic education for all children.