This volume focuses on research in education in the Basque Country where Basque is very often the language of instruction for some or all the school subjects. The volume provides background information about the Basque educational system; about academic and linguistic results related to the use of Basque as the language of instruction and the challenges and problems the Basque educational system is currently facing. The volume focuses on research conducted in the Basque Country that can be useful for other bilingual and multilingual contexts involving different language combinations. The articles look at the achievements of the last 25 years but also discuss the challenges the Basque educational system is facing nowadays.