The expansion of choices available to low-income families seeking primary education for their children has been one of the striking changes seen along the uneven path towards quality Education for All. This guide, produced by Business Fights Poverty in partnership with Endeva, BRAC, CDC and DFID, is written primarily for potential investors in low-cost private education. It focuses on what can be done to help improve that contribution, putting in place the conditions under which low cost private schools can equitably and sustainably deliver better outcomes for poor communities. We suggest it is possible to do so in ways that will further strengthen national education systems as a whole. Investors can bring much-needed new resources and also have some influence, both with education providers and regulators. The guide identifies the potential roles of investors in supporting a variety of potentially scalable solutions, ranging from direct investment in chains of schools through to strengthening systems for information that can drive new forms of accountability. The guide seeks to offer investors an overview of approaches that appear promising in strengthening both quality and inclusiveness of primary schools funded by low fees.