This book focuses on Hong Kong as a multilingual society. It investigates how trilingual education is implemented in Hong Kong primary schools. Based on a large scale survey of 155 Hong Kong schools and in-depth case studies in 3 selected schools, the book gives an overview of trilingual education in Hong Kong primary schools, revealing the views on trilingual education of all stakeholders: school principals, panel chairs, subject teachers, students, and parents. The research findings presented in this book suggest that the implementation of trilingual education varies significantly from school to school, as does the effectiveness of the trilingual education models used. It shows how students’ views towards the use of different media of instruction (MoIs) also vary, and how their mother-tongue backgrounds affect their perceptions. By documenting views, policies and implementation methods, the book provides insight into the practice of trilingual education in Hong Kong and offers suggestions on potentially effective implementation methods. Copyright © 2019 Springer Nature Switzerland AG.