Within linguistics and educational research, language awareness (LA) has been studied for decades. Despite the extensive use of the concept and several conceptualizations, 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 conceptualization of LA across educational levels in the context of plurilingual education and, based on the conceptualization, 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 multiple-case study, interview data are coded and analysed through a qualitative content analysis. The case study found that students across educational levels expressed 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 drew 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 that are not represented in the educational system.