While multilingual programmes have been implemented in early childhood education in several countries in Europe, professionals may still be unsure of how to promote multilingualism and deal with language diversity. There is a need for professional development (PD) which can influence the practitioners’ attitudes, knowledge and skills, and the quality of their teaching (Egert et al., 2018; Peleman et al., 2017). This presentation begins with an outline of several theoretical models of PD and explains why integrated models that are collaborative, inquiry-based, and performance-based are the most effective in contributing to change. I will then present a PD used in Luxembourg to help early childhood practitioners develop and implement multilingual pedagogies. The model, which comprised training sessions, network meetings, and coaching, aimed to deepen the practitioners’ understanding of multilingualism and language learning, familiarize them with translanguaging (García & Reid, 2019) and enable them to implement language and literacy activities in Luxembourgish, French and children’s home languages (Kirsch et al. forthcoming). Finally, I provide insights into the professional learning of two preschool teachers. The PD, the experience of engaging in multilingual activities, and the reflection on teaching and learning, enabled the teachers to develop a positive stance to multilingual education, design productive leaning environments based on social-constructivist theories, and monitor language use to guarantee responsible translanguaging (Kirsch 2020).