peer reviewed ; While multilingual programmes have been implemented in early childhood education in several countries, professionals have shown to be unsure of how to deal with language diversity and promote home languages. Therefore, there is a need for professional development. The present article discusses the outcomes of a professional course on multilingual education in early childhood delivered to 46 early-years practitioners in Luxembourg. Using a questionnaire administered prior to and after the course as well as interviews, we examined the influence of the training on attitudes to multilingual education and activities to develop Luxembourgish and home languages. The analysis drew on content analysis, paired samples t-test and correlational analysis. The findings show that the course positively influenced the professionals’ knowledge about multilingualism and language learning, their attitudes towards home languages, their interest in organising activities in the children’s home languages and the implementation of these activities. The results shed light on special interest areas such as the quality of input that future professional development courses could focus on. ; Developing of multilingual pedagogies in early childhood