Most of the world is multilingual--multilingual at the national level (policies), at the community and family level (practices), and at the individual level (cognitive)--and each of these has implications for teaching and learning. Yet, at present, most reading decisions are not based on empirical research of how children learn to read in multilingual contexts. Several large-scale assessments of reading at early grade levels have shed light on the extremely low reading scores that many countries in the developing world have across these multilingual contexts. The reasons for these low scores are multifaceted; however, the most central unanswered question is which languages should be taught--and how and when--in multilingual contexts? To begin addressing this need, the "Facilitating Reading Acquisition in Multilingual Environments in India (FRAME-India)" research study examined the process of acquiring literacy in multilingual environments. Findings from this study are converted into policy and practice guidelines for effectively and quickly improving reading outcomes. This is one of the first studies to focus on formative, pre-intervention research for developing a theory of change that is relevant for multilingual learners in the developing world. While continuing to conduct rigorous impact evaluations, technical assistance, and program design and implementation, the authors emphasize that there must be a focus on understanding the mechanisms of learning that underpin successful reading acquisition in contexts characterized by multilingualism and limited resources. This is extremely important in order to construct successful programs that are likely to benefit millions of children who are learning in these multilingual environments every day. The following are appended: (1) Test Item Construction Details; (2) Sample Items from the Tests and Photos of Data Collection Activities; (3) Training Agenda for Data Collectors and Hub Monitors; (4) Flowchart of Test Eligibility Criteria; and (5) Means, Standard Deviations, and Summary Statistics for All Reading Subskills. [World Vision International also contributed support for this study.]