Theory of mind competence and knowledge of emotions were studied longitudinally in a sample of preschoolers aged 3 (n=263) and 4 (n=244) years. Children were assessed using standard measures of theory of mind and emotion knowledge. Three competing hypotheses were tested regarding the developmental associations between children's theory of mind abilities and their knowledge of emotions. First, that an understanding of emotion develops early and informs children's understanding of others’ thinking. Alternatively, having a basic theory of mind may help children (...) learn about emotions. Third, that the two domains are separate aspects of children's social cognitive skills such that each area develops independently. Results of hierarchical regressions supported the first hypothesis that early emotion understanding predicts later theory-of-mind performance, and not the reverse. (shrink)