Teaching curricular content in a foreign language within the education system requires teachers to possess a series of skills that have not yet been identified in the educational orders responsible for profiling teaching figures in Spain’s compulsory schooling system. Having located a series of national and international documents that make reference to certain competences required by CLIL teachers, we find there is a lack of empirical or contextual validity in these proposals. Hence, the aim of this paper is to identify empirically the set of specific competences required to successfully teach curricular content through the medium of a foreign language.