The empiric multilevel model presented in this paper intertwines sociolinguistics and school effects research, using insights from both fields. Sociolinguistic research has shown that school culture regarding multilingualism can have an important impact on pupils’ well-being. As language is part of pupils’ identity, they may feel uncomfortable or demotivated when (the use of) their mother tongue is pointed out as the cause of lower school success. A school culture, however, that embraces and exploits the multilingual reality may cause pupils to perform and feel better, as they are given the possibility to use their foreknowledge in the learning process (Cummins, 2001). School effects research has focused on teachability expectations teachers hold of pupils (Becker, 1952), suggesting multilingualism as an important factor in shaping those expectations (Agirdag, Van Avermaet, & Van Houtte, 2013). This paper focuses on how managing the linguistic diversity in a school motivates teachers for creative approaches to manage children’s multilingual repertoires and on how it inspires teachability expectations. Furthermore it reports on the impact that managing linguistic diversity has on pupils’ cognitive and non-cognitive outcomes. The analysis in this multilevel model originate from a survey in 67 primary schools in which teachers and 4th grade pupils participated.