Mothers' emotion talk, children's emotion talk, and children's understanding of emotion were examined in 50 mother-child dyads at 41 months. Language measures included total emotion words, unique emotion words, labels, explanations, and different types of explanations. Children's emotion understanding was assessed for labeling, situation, and role-taking knowledge, as well as an overall score. There were different patterns of relations between mothers' emotion talk and boys' and girls' emotion talk, with mothers' emotion talk related more strongly to boys' emotion talk. Mothers' emotion talk for boys and girls was differentially related to the subparts of the emotion understanding test. Specifically, mothers' total emotion talk predicted boys' performance on the situation knowledge test and their use of causal emotion explanations predicted boys' overall score, but none of the maternal variables predicted girls' performance. This finding may result from differences in variability of maternal speech to boys' and girls', and it may be due to differences in maternal speech in earlier years.