English language education in Brazilian private school systems is undergoing changes.

Several school systems have opted for the implementation of an American high school curriculum using a Content-based Instruction (CBI) or Content and Language Integrated Learning (CLIL) curricular framework within which students apply their language skills to learning subject specific academic content. High School International (HSI) is one of the providers of a CLIL curriculum. In this descriptive case study of the implementation of the HSI CLIL curriculum in a private boarding school in the Southeast of Brazil respective stakeholders were interviewed and their experiences have been described and analyzed. Certain critical aspects have been identified. Involvement of the school principal and administration is one of the key ingredients of a successful implementation. Planning the implementation months in advance, such as preparing the curriculum, course outlines, and schedules, training of teachers, staff, and academic coordinator, definitely eases the whole process.