Content and Language Integrated Learning (CLIL) bilingual education programmes have gained significant attention in educational policy and practice across Europe (European Commission et al., 2023). These programmes, which aim to integrate subject and language learning, have been promoted since the early 2000s. One of its main o at the EU level to democratize access to second language learning (Barrios, 2019). However, their impact on equity and equality of opportunities remains a contentious issue. Critics argue that CLIL-based educational programmes can exacerbate educational inequalities (Bruton, 2013) for multiple reasons. Among others, access to these programmes is often determined by socio-economic background, parental education levels, and geographic location. The demand for bilingual programmes tends to be higher among privileged socio-economic groups, leading to an unequal distribution of CLIL opportunities. This raises concerns about whether CLIL inadvertently reinforces existing disparities in educational outcomes.

Despite the considerable time since the implementation of CLIL and the extensive literature on the subject, what evidence is available regarding the impact of CLIL on educational equality and inequality? What is the extent of the results in relation to the validity of the studies that support them? What are the main strengths and weaknesses of the studies conducted and the available findings?

This work addresses this gap by systematically reviewing empirical studies that investigate the impact of CLIL on educational equity and inequality. It examines the accumulated evidence in three main dimensions: school demand, academic results, and school supply. Specifically:

(1) Whether participation in CLIL is egalitarian in terms of social background and academic abilities, or whether it leads to selection or self-selection processes that may result in educational segregation.

(2) The effect of CLIL on the academic performance of students from diverse social backgrounds, with a view to assessing its suitability for less advantaged students, or whether it causes learning deficits and exacerbates educational inequality.

(3) From a supply standpoint, whether the distribution or characteristics of schools that provide CLIL are biased by socio-economic context variables.

A critical approach to the sampled studies focuses on assessing the validity of the evidence regarding CLIL's potential elitism and its impact on equality of opportunities. This involves an evaluation of the methodological rigor of the studies under review.

This study aims to provide a foundation for future research, contributing to ongoing discussions on whether CLIL programmes promote or challenge educational equity and inclusiveness, while highlighting areas where further clarity is needed.

This systematic and critical review (Grant & Bootht, 2009) adopts an aggregative approach to compile and analyse empirical evidence on the equity effects of CLIL programs for English as a second language in Europe, aiming to understand their magnitude and variability (Gough et al., 2012). The review includes studies from the Web of Science and Scopus databases, yielding 34 references. Inclusion criteria were empirical studies (quantitative, qualitative, or mixed) focused on the European Economic Area, UK, and Switzerland, published in English before 2024 in peer-reviewed journals. Keywords were organized into four themes: CLIL’s equity effects, school organization (streaming and tracking), CLIL’s relation to social background, and CLIL supply and demand in schools. Two researchers independently applied these criteria, resolving discrepancies collaboratively. The categorization system, designed a priori but flexible for emerging insights, is based on three dimensions: demand, supply, and competences/achievement. Demand includes student selection and psychosocial factors; supply examines equity in CLIL provision based on school characteristics; competences/achievement assesses impacts on academic performance and psychosocial variables. Three researchers independently coded the articles, achieving consensus through comparative sessions. The analysis involved descriptive bibliometrics using Bibliometrix and content analysis, evaluating geographical scope, category distribution, methodologies, educational levels, and findings on elitism in CLIL programs.

The review findings indicate that the study of CLIL programmes is still in an early stage of development. The research is limited in number, highly concentrated in specific geographical areas, disciplines, and methodologies. From a disciplinary perspective, the field is dominated by experts in bilingual education, teacher training, and linguistics, while contributions from sociology and economics, which are crucial for analysing educational inequalities, remain minimal. Methodologically, the research relies heavily on quantitative designs, with qualitative studies being underrepresented. This lack of qualitative research limits understanding of the processes and strategies underlying educational inequalities and hinders the exploration of mechanisms generating such disparities. The review also identifies an imbalance in research focus. Most studies concentrate on demand-side factors, such as elitist biases in student selection based on prior academic performance and socioeconomic status. These studies converge in finding that CLIL tends to attract students with higher academic abilities and from privileged backgrounds, contributing to educational segregation. However, evidence on the academic and linguistic impact of CLIL is mixed and inconclusive. A significant research gap exists regarding the supply side, which affects the interpretation of school selection processes. Finally, this systematic review also adopts a critical approach, aiming to uncover gaps and inconsistencies in the epistemological and methodological approaches underlying the sampled studies, highlighting significant limitations that affect both internal and external validity. Firstly, it is evident that a significant proportion of the studies (which are predominantly quantitative) exhibit substantial limitations with regard to their sample design. The most prevalent limitations are: non-probability sampling, design issues in quasi-experimental studies, sampling biases, and small sample sizes.

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