This study focuses on metalinguistic awareness (MLA) and its relation to academic achievement for mono-, bi- and multilingual adolescents in Denmark. While MLA is one of several cognitive measures positively related to bilingualism and bilingualism is associated with academic advantages, Danish bi-/multilingual pupils appear not to benefit from their knowledge of more languages as they lag behind their monolingual school peers. Therefore, this study aims to depict the distribution of MLA between different linguistic groups in a Danish school context and to determine whether there is a correlation between MLA and academic achievement. Additionally, the relationship between socioeconomic status and test results is investigated. Participants are categorised according to the languages they report using actively. 219 pupils aged 14-16, 106 monolingual and 113 bi-/multilingual, completed a questionnaire and a test of MLA, both in Danish. School leaving exam results and a measure of socioeconomic status were also obtained. While results show no distinct bi-/multilingual advantage on the test of MLA, a strong correlation between school leaving exam results and MLA is found. Furthermore, Danish proficiency and socioeconomic status accounts for some of the variation in test results, thus moderating test performance differences found between groups.