With its Early Years Preschool Program (EYPP), Save the Children has been providing the additional year of preschool to children at age 4. Children then begin the typical one-year pre-primary class at age 5 and to Grade 1 at age 6. This study aims to investigate the impacts of offering this additional year of pre-primary education in Bangladesh on child development outcomes and examines the benefits relative to the costs of the program. The study also examines the mechanisms through which the EYPP affects the outcomes of interest (e.g., children’s school readiness) and the operational and community conditions for program implementation.