Within linguistics and educational research, language awareness (LA) has been studied for decades. Despite the extensive use of the concept and several operationalizations, systematic empirical research examining students’ LA across educational levels in the context of plurilingual education is still lacking. The article seeks to fill this gap by introducing a theoretically and empirically based operationalization of LA across educational levels in the context of plurilingual education and, based on the operationalization, presents findings from a within- and cross-case analysis exploring students’ expressions of LA in primary, lower and upper secondary education. As part of an exploratory embedded and replicated multiple-case study, interview data are coded and analysed through a qualitative content analysis. The case study finds that students across educational levels express metalinguistic awareness (MLA) and critical language awareness (CLA) revealing similarities and differences in respect to the learners’ age and language resources as well as signs of complexification, e.g. through more nuanced MLA expressions and concretisations reflecting that the students draw on a broader range of experiences. The students’ MLA and CLA are framed by the students' plurilingualism representing a diversity of language resources, while also showing a preoccupation with languages not represented in the educational system.