This volume investigates the policy and practice of medium of instruction at different levels of education in Asian polities including Bangladesh, Hong Kong, India, Indonesia, Japan, Malaysia, the Maldives, Nepal, Timor-Leste and Vietnam. The chapters provide an informed understanding of the context, process, actors, goals and outcomes of medium of instruction policies from a language policy and planning perspective. The volume has an emphasis on the exploration of medium of instruction in action which brings into focus the perspectives of micro policy enactors including teachers, students, and parents in the local context, generating crucial empirical insights. This critical analysis of the goals, outcomes and experiences of this trend in global language-in-education will be of interest to language and education students, researchers, practicing teachers, executives in academia and language studies and to education policymaking authorities in Asia and other parts of the world. The volume updates existing research on medium of instruction and takes the field forward in a fast-changing world as English medium instruction policies are globalised. This book was originally published as a special issue of Current Issues in Language Planning.