Self-expression is a key concept for sociological studies on childhood since it is the cue for children's self-socialization and agency. Hence promoting children's agency and social participation requires their self-expression to be facilitated in their interaction with adults. The analysis in this article of a set of interactions in Italian schools sheds light on how promotion of children's self-expression succeeded or failed through specific adult intervention and forms of communication. This analysis may be interesting for a reflection on how to promote children's participation and self-expression in education systems.