This article starts with a definition of the field and the identification of the main agents that play a social role in language-in-education policies, and then moves to review the evolution and the state of the art of educational sociolinguistics research in the Catalan-speaking territories. The article surveys the main theoretical and applied debates during the Republican period in the 1930’s, the controversies about language and education in the late period of Francoist dictatorship, the many challenges associated with the definition of a school language model in the early decades of the autonomy between the 1970’s and the 1980’s, the development of a plurality of research studies connected, among others, with sociological and ethnographic perspectives, and the growing role of linguistic and cultural diversity in the first two decades of the 21st century. The article ends with a critical balance of achievement and what-to-does in the field.