This report presents findings from a two year randomized control trial of Save the Children's Literacy Boost intervention in Rwanda. Literacy Boost provides regular, in-service teacher training on effective practices in early primary literacy instruction. It also engages children, families, and communities in activities to better support children learn outside school walls. It further provides local language reading materials in the schools and central community locations. The main research questions of the study were: (1) What is the impact of teacher training on children's reading development? and (2) What is the added benefit of engaging families and communities in children's learning? To answer these questions, sectors within one district in Rwanda were randomly assigned to participate in one of two treatment groups or a control group. One group received teacher training activities only (the TT group), while another received both teacher training and community action activities (the LB group). A third group served as a control. The research included a variety of methods to estimate impact, including longitudinal reading assessments, teacher surveys, teacher observations, home surveys, and home observations. The findings indicate that treatments had an impact on repetition rates, oral comprehension skills, reading fluency and reading comprehension. The largest observable impact across a range of outcomes was found in the LB group, although results still showed a large group of children struggling to read after three years in school across all groups. The findings suggest a need for the education community to expand beyond the school walls in efforts to address the learning crisis.