Abstract Introduction As part of the flourishing line of enquiry into children's emotion understanding, we report the results of a conversation-based intervention study aimed at improving participants’ emotion comprehension, and exploring the intervention effect as a function of attachment security. Method The study was conducted at school with the participation of 98 second-grade children (mean age: 7 years, 7 months; SD: 3.4 months). Participants were assigned to experimental and control groups that were balanced with respect to attachment security and insecurity as evaluated using the Separation Anxiety Test (SAT). The experimental group was exposed to a conversational intervention, in which short story readings with emotional content were used to stimulate discussion on the nature, causes and regulation of emotion. The children in the control group listened to the same stories, but did not take part in the conversational activity. Children from both groups were individually pre- and post-tested on measures of emotional lexicon (ELT) and emotion comprehension (TEC). Results The training was found to have a significant effect on the emotion comprehension of the children allocated to the experimental group. In addition, non-secure children displayed higher gains in emotion comprehension than secure participants. The implications of the findings for educational and school contexts are discussed.