Individual differences in children's emotion understanding have been intensively investigated during the past decade. Theses studies suggest that individual differences emerge quite early, are present among both preschool and school children, are not restricted to the understanding of some specific components of emotions, correlate with other characteristics of the individual and his or her social network, and may persist even after an intervention program. However, because few of these studies had a longitudinal design we know little about change and stability in these individual differences especially among school-aged children when several components of emotion understanding, both simple and complex, are assessed. Therefore, the two aims of the present study were to examine both change and stability in individual differences among school-aged children in their understanding of several components of emotion. For this purpose, 42 children aged 7, 9, and 11 years at Time I were re-tested 13 months later at Time II on several components of emotion understanding, both simple and complex, with the Test of Emotion Comprehension (TEC). The results show that: (1) The two younger age groups clearly improved their overall level of emotion understanding; (2) this improvement was not equally distributed across the different components of emotions understanding; (3) individual differences in the overall level of emotion understanding were very stable, with overall level at Time I being a good predictor of overall level at Time 2; and (4) this stability was observable for both simple and complex components of emotion understanding. Some of the results of this research have been presented at the Harvard University (Pons, 2003) and the University of Montréal (Pons & Harris, 2003). This empirical research is still running. With Paul Harris (Harvard University).