Abstract CLIL (Content and Language Integrated Learning) has grown steadily in Europe through different methodologies. From the perspective of language education, the active participation of students has been on the increase. Nowadays, primary, secondary and tertiary curricula in Spain, the Common European Framework of Reference for Languages (CEFR) (Council of Europe 2001) or the European Space for Higher Education propose a much more active student’s role and the development of the learner’s autonomy. The Multilingualism Programme (MP) is part of the strategic plan for the internationalisation of the University of the Basque Country (UBC). One of the objectives of this strategic plan is to continue at tertiary level with the trilingual programmes (CLIL) increasingly implemented at secondary education level. CLIL is mushrooming at pre-university level and this approach has to be researched so that well-informed decisions can be made regarding its implementation (Doiz et al. 2011), and future university students can fully benefit from English-medium instruction. However, there is a dearth of research on CLIL programmes founded on cooperative project work in our context, and reflection on real classroom practice is needed (Doiz et al. 2014; Sierra, 2016). In this paper, I first present the characteristics of a cooperative project CLIL programme carried out at a secondary school in the Basque Autonomous Community, Spain. Then, the opinions of 431 students about their learning experience over a six-year implementation period (2008-2014) are analysed. The participants expressed their perceptions about the course; their degree of motivation and amount of work; their improvement on language skills and content learning; their experience in cooperative groups and the quality of their autonomous learning. Finally, some pedagogical implications are put forward which may help improve CLIL classroom practice. These proposals could also be helpful for language learning classrooms. References Council of Europe (2001). Common European Framework of Reference for Languages: Learning, Teaching, Assessment. Cambridge: Cambridge University Press. Doiz, A., Lasagabaster, D. & Sierra, J.M. (2011). Internationalisation, multilingualism, and English-medium instruction. World Englishes 30(3), 345-359. Doiz, A., Lasagabaster, D. & Sierra, J.M. (2014). CLIL and motivation: The effect of individual and contextual variables. Language Learning Journal 42(2), 209–224. Sierra, J.M. (2016). Cooperative projects in a CLIL course: What do students think? In D. Lasgabaster and A. Doiz (eds) CLIL experiences in secondary and tertiary education: In search of good practices (pp.69-97). Bern: Peter Lang.