In Guatemala, many girls attend no school. A project by the United States Agency for International Development (USAID), Basic Education Strengthening (BEST), demonstrated that improving educational quality is the best approach to enhancing girls' participation. BEST included a Girls Education Program (GEP) activity. Under the BEST/GEP umbrella, several new strategies were tried, most notably mobilizing the private sector to action for girls' education and testing targeted interventions to improve the education of indigenous rural girls. Section 1, "Introduction," describes the problem. Section 2, "Background," discusses the war and the peace accords and examines the problem. Section 3, "USAID and Girls' Education in Guatemala," describes project implementation. Section 4, "CDIE Study Methods," describes the impact evaluation conducted by USAID's Center for Development Information and Evaluation (CDIE). Section 5, "BEST/GEP Successes and Shortcomings," describes program results. Section 6, "Findings: BEST/GEP Program Components," examines program components: the Franja Curricular (systemwide interventions to integrate gender issues); Eduque a la Nina (GEP's major component); bilingual education; Nueva Escuela Unitaria (improving learning via flexible individual and group study and active participation); technical assistance; and cost effectiveness. Section 7, "Findings: BEST/GEP Policy Initiatives and Outcomes," examines policy dialog and project conditionality, policy reform, private sector participation, donor coordination, sustainability, missing actors, and benefits to boys. Section 8, "Conclusions," discusses synergies unrealized and USAID's comparative advantage. Section 9, "Lessons Learned," discusses points that underscore GEP's two principal lessons regarding the need for broader and deeper participation and for concentrating on systemwide sustainable impacts. (SM)