This report is intended for senior Ministry of Education officials and national leaders concerned with education in linguistically diverse countries, as well as donor agencies supporting basic and post-basic education in low and middle income countries. The report considers the extent to which the language used for teaching and learning can be a key barrier or enabler in achieving national and international education commitments. It examines the most appropriate policy and investment actions for national governments, and discusses the challenges which might be experienced in pursuing good practice around school language. The report assesses the extent to which donor agencies are supporting or undermining efforts to address problems with school language, and presents recommendations for international collaboration to produce more strategic action to remove the language barriers which keep many children from progressing through education.