In ELT literature, the reader often finds the terms Content and Language Integrated Learning (CLIL) and immersion used interchangeably, even though there are important differences between them. These two labels usually appear as generic terms covering any kind of teaching in which an L2 is used to teach content. In this article, we attempt to unravel this ambiguity from the Spanish context, describing from a psycholinguistic and methodological point of view the aspects they share and, above all, their main differences. Although CLIL can be implemented in different foreign languages, the fact is that English is the language overwhelmingly used as a means of instruction in most European countries (Eurydice. 2006. Content and Language Integrated Learning (CLIL) at School in Europe. Brussels: European Commission).