Learning outcomes are low and instruction poor in many low- and middle-income countries (LMICs). Although the number of successful programs is growing, relatively few have demonstrated impact at large scale. The Learning at Scale study was designed to identify existing programs with demonstrated impact on basic skills at scale and to conduct in-depth investigations of these programs to determine what makes them successful. The Learning at Scale study focuses on two areas: (1) identifying instructional strategies that are essential for improving learning outcomes at scale in LMICs and (2) learning about the characteristics of the systems within which successful, scaled-up programs operate. Our research is designed to achieve these two goals by studying eight of the most effective large-scale education programs in LMICs.