RESUMEN
Parental reflective functioning refers to the parents' ability to reflect on the internal mental states of their children, which will make them respond more sensitively to their children´s need. The relation between parental reflective functioning and child emotion regulation has been considered a key factor in early childhood parenting but further research is needed about this relationship throughout child's development. The aim of this paper was to analyze this interaction considering the early childhood development stages. Three hundred and eighty one mothers of babies between 0 and 26 months of age participated in the study. The PRFQ and ASQ:SE-2 questionnaires were administered to assess parental reflective functioning and child emotion regulation, respectively. Results showed that maternal RF and child emotion regulation do not follow a linear process according to the childhood development stages, and also that the maternal PM dimension generates a conditional effect in children's emotion regulation. These results highlight the importance of paying attention to specific early childhood developmental stages to understand how maternal reflective functioning influences child´s ability to calm and adjust to her/his environment.