Educational disparities between pupils with and without an immigrant background within most school systems in Europe have been attributed to the insufficient proficiency in the language(s) of schooling of the host societies. It will be claimed that the forms of teaching and learning also make a decisive difference. Explicit teaching aim at regulating cognitive processes of learners and involve activities such as sequencing and making content-related aspects explicit throughout the class, which has been proved as beneficial for vulnerable learners (Einsiedler/Hardy 2010). The advantage of explicit teaching is also supported by Stern’s (2009) argument that implicit learning occurs permanently, is time consuming and related to personal experiences. Explicit learning, however, is not based on personal experience but on social interactions. These insights are complemented well by research on successful teaching and learning in bi- or multilingual constellations (Norris/Ortega 2000), also with respect to subject matter (Gibbons 2003). The paper presents results of a video study (59 hours) conducted in subject-matter classes (10th grade) and addressing the issue of explicit teaching in multilingual school constellations. Results suggest that the lack of explicit teaching leads indeed to misunderstandings, frustration and extra time needed in class to clarify tasks and outcomes.