This paper presents a rigorous review of evidence on the role and impact of private schools on the education of school-aged children in developing countries. The focus of the review is on private school delivery of education to poorer sections of societies, including private schools identified as low-fee private schools (LFPs). The strength of the evidence is assessed and gaps are identified which highlight areas for further research. Following an initial sifting of the literature which produced extensive results, parameters were set by the review team to further narrow focus. Literature included in this review has therefore been published in the past five years, sourced from DFID priority countries, and includes only research judged to be of high or medium quality. Some 59 studies were included in the final analysis. The research question driving the review is: Can private schools improve education for children in developing countries? The conceptual framework set out a number of hypotheses and assumptions that underpin the polarised debate about the potential and real contribution of private schools. These are interrogated through a rigorous and objective review of the evidence and findings are mapped on to an evidenced theory of change.