Despite its non-elitist goals, there is growing concern over the potentially elitist nature of content and language integrated learning (CLIL) programmes in English. Previous European studies have reported more advantaged pupils' profiles in these programmes compared to regular programmes. It is unclear from the literature however which pupils have access to CLIL programmes based on the choices made at the school level. In order to remedy this gap in the current literature, the present quantitative study analysed all 948 secondary schools in the Flemish Community of Belgium based on three main categories of predictors: home language, socio-economic status (SES) and school size. Resulting of a stepwise logistic regression analysis, only SES and school size appear to be strong predictors of the presence of an English CLIL programme. In a region where low-SES pupils have an average of three-year delay in development in comparison to their high-SES peers (Franck and Nicaise 2018), the identification (and transformation) of these kinds of selective mechanisms is crucial to reaching educational equity. We relate these mechanisms to some specific characteristics of CLIL in the Flemish Community of Belgium, which may also apply, to some extent, to other educational contexts in Europe.