The study (N = 92) piloted an inclusive programme taking advantage of linguistic diversity in regular primary classrooms in Geneva (Switzerland) to reinforce classroom social climate. The same three-stages programme (activities for opening to others, activities for opening to linguistic diversity, and multilingual cooperative activities) was introduced in three classes, while adapting the content of the activities to different grades (grades 3 to 5). Results indicate that this programme protected against the decrease in the feeling of belonging to the class and in the perception of social relatedness which appeared without the programme in three control classes.