Complementary schools for immigrant and ethnic minority children in the UK have been an important socio-political, educational movement in the country for nearly half a century. They have made a major impact on the lives of thousands of children of different ethnic backgrounds, attracted public debates vis-a-vis the government's involvement in educational management, and challenged the dominant ideology of uniculturalism in the country. Yet, they have received relatively little attention from educational researchers. The present special issue, focusing on language and interaction in a selected group of complementary schools in England, provides new impetus for more research in this particular area. In this short discussion paper, I will first outline the socio-political histories of complementary schools in the UK. I will then look at some of the key issues emerging from these schools and from the studies that are published in the present volume. Finally, I will discuss what kinds of research should be done in the future that will inform both the policies and practices regarding complementary schools and the public debate over multilingual and multicultural education in the country.