The main aim of the present project is to explore gender differentiation in the actions of children in transition between kindergarten and primary school. We propose a sociocultural approach to the topic, yet addressing the consequences of the debates in gender studies for theory building in developmental psychology. This means that we will study how cultural guidance takes place, by a semiotic analysis of children’s actions. To address gender differences from this angle we will pay attention to three different perspectives: the child’s perspective, the study of the environment in which children live (how it is organised), and concrete interactions (peer- and adult-child interactions). The methodology is qualitative and includes interviews and ethnographic observations. These will be done with a particular focus on play scenes where we’ll try to identify evolving themes in gender-marked play. The project involves a longitudinal in depth case study of children finishing kindergarten and starting primary school. We follow targeted children in school and outside formal settings of education. Our general aim will thus be to identify elements participating to the progressive appearance of gender differences in children in transition between kindergarten and primary school. We will thus trace back these elements to peer- and adult-child interactions, daily life situations, experiences and the child’s perspective, possibly contributing to a better understanding of how gender participates of child development.