This project is based on research about foreign language teaching and learning and aims to contribute to the advancement of knowledge in the realm of bilingual education, where the foreign language (English), apart from being the target language, is used as the language to teach other content subjects. This educational approach known as CLIL (Content and Language Integrated Learning) has increasingly become very popular in Spain. In the northern region of Cantabria, there are several bilingual schools in both Primary and Secondary Education and the University of Cantabria has also increased the number of subjects taught in English in its various degree and master programmes. This project aims to analyze different aspects of the implementation of CLIL in Cantabria at all levels of education (Primary, Secondary and Tertiary). Firstly, in Line of Research 1, «The Acquisition of Communicative Competence in CLIL: A pseudo-longitudinal Study in Primary Education», the target is to explore the nature of various linguistic dimensions of English competence in Primary Education students who are distinguished by their age, amount of exposure to English and type of instruction (more and less intense CLIL and non-CLIL). With the title «From Communicative Competence to Intercultural Communicative Competence: Exploring Intercultural Skills Training in Bilingual Programmes at the Secondary Level», Line of Research 2 is meant to prove that bilingual CLIL programmes are the ideal setting for the direct incorporation of intercultural training strategies and activities at the Secondary Level, and that both teacher training and sustained and meaningful contact with persons from other cultures are necessary to ensure that intercultural competence training is truly effective. The third Line of Research entitled «From Bilingual Teaching to CLIL: Teaching Strategies and Teaching Portfolios for Bilingual Teaching at the Tertiary Level» follows a qualitative approach based on individual in-depth interviews in order to test the feasibility of the methodological guidelines of the CLIL approach for tertiary education and to develop a self-assessment portfolio suitable for Higher Education.