Although laughter and smiling is generally thought of in terms of positive emotions and values, this is not always the case. In this paper we analyze situations where children’s smiling and laughter are treated as undesirable by other participants—peers and teachers—in preschool and school settings. Participants’ treatment of children’s laughs and smiles as accountable, even sanctionable, provides one piece of the larger puzzle of how emotional expressions form an emerging social competence, negotiated and co-constructed in and through social interaction. The analysis shows how emotional expressions such as laughter and smiling are part of, and subject to, processes of socialization, i.e., social knowledge about embodied moral norms