This research is about six pedagogue´s and their reflections about the size of the children´s group in the preschools. Then I will discuss the pedagogue’s recommendation on the significance of the size of a children´s group learning and development and it´s practical significance for the preschool function. The pedagogue’s statements will be discussed in relation to The Swedish National Agency for Education (TSNAE) guidelines on group size. The theoretical framework of this essay will take an overview of the social cultural perspective, the group size and its significance for both the children´s learning and development, for interaction and communication and TSNAE advice and guidelines. A qualitative approach was used including six interviews in Stockholm. The result of this research shows that the six pedagogue´s concluded that the size of a children´s group can vary according to circumstances but 15 - 18 children are recommended and that is also supported by TSNAE. There is no exact recommendation for an ideal group size from TSNAE, but their guidelines for a group size is based on that children will development on an optimal way. For the pedagogue´s will be able to hear and listen to all children, the pedagogue´s think that it´s important that this can be done if the children group is divided in smaller groups during the day. This is also important for the interaction and to have discussions with the children. It is difficult to individualize the children if they are too many children in the group.    TSNAE general advice for quality says that the children´s group should be suitable size. The size will be according to the preschools prerequisites.