ABSTRACT This study examined Chinese preschoolers’ affective experiences during organized activities. One-on-one child interviews were conducted in which children were asked to rate their general affect during each organized activity in which they participated, and then provide reasons for their responses. Child-reported emotional engagement was related to children’s social-emotional development, approaches to learning, as well as cognitive development. The reasons children mentioned for both their positive and negative affect were coded into six major categories: interest-utility value, activity format, activity difficulty level, interpersonal relationships, external reinforcement, and activity arrangement. Notably, interest-utility value was most frequently used by children to explain their positive affect, while difficulty level was most frequently cited to explain their negative affect. The findings underline the need to better understand young children’s organized activity experiences from their own perspectives, as well as the importance of children’s affective experiences during organized activities for their development in multiple domains.