The project Spaces for multilingualism is founded by the Swedish Research Council (2022-2026). The purpose of the interdisciplinary project is to generate knowledge about the pedagogical potentials and limitations of multilingual practices in mathematics and science education. We specifically aim to explore and problematise how multilingual approaches and activities may promote mathematics and science teaching and learning in school years 4–9. The qualitative project is conducted by an interdisciplinary research team that integrates theories from educational research in didactics, sociology and linguistics, including translanguaging theories. The project’s four-year period comprises initial exploration of existing pedagogical practices, mainly through workshops with teachers, classroom observations and interviews with students and teachers, in four culturally and linguistically diverse schools. This explorative phase is followed by a two-year period of pedagogical interventions, in which teachers and researchers together design, carry out and analyse classroom interventions. The interventions involve exploring the pedagogical potentials and limitations for promoting multilingual resources for teaching and learning. Further, students’ identities as engaged learners of mathematics and science are explored. Our ambition is for the project to contribute with new and multifaceted knowledge on the complexity of teaching and learning in multilingual mathematics and science classrooms in mainstream compulsory schools in which the students have a variety of language backgrounds. The presentation will focus on the explorative phase of the study and the preliminary results from interviews with students and teachers as well as workshops in which teachers and researchers collaborated. We will also present the ongoing preparations for the interventional phase of the study.