How do teachers deal with multilingual pupils, and what reasons govern these choices? Whereas most studies on this topic have examined teachers in schools with monolingual policies, this paper includes teachers at bilingual schools. Framed by pedagogical theory, we present a qualitative research study based on interviews with teachers in the German state North Rhine-Westphalia (NRW). This area constitutes an interesting research site since 30-50% of the children are multilingual, but language policies in schools differ: Whereas most schools have a monolingual orientation, bilingual schools aim to purposely integrate languages beyond German in regular classes. Our results show that despite the differences in school language policies, despite different professional biographies and independent of knowledge on multilingual upbringings, teachers in mono- as well as bilingual schools reproduce the unquestioned perception of a monolingual norm. Furthermore, teachers at bilingual schools focusing on European languages deem migration-induced multilingualism as even less important than do teachers at regular schools. Finally, the results underline the importance of institutional policies and allow for insights into individual logic. On a larger horizon, the study contributes to issues of language-responsible teaching, equal opportunities, educational equality and social cohesion.