Research Findings: The present study investigated the relation between theory of mind (ToM) and emotion understanding among 78 children 4 1/2; to 6 1/2; years old (35 boys, 43 girls). ToM understanding was assessed using ignorance and false belief questions within an emotion-understanding task that evaluated children's abilities to recognize facial expressions and identify the external causes of emotions (happy, sad, angry, scared, and surprised), understand the role of beliefs and desires in emotion, and comprehend felt versus expressed emotions. Results indicated that children's understanding of the external causes of emotion, hidden emotions, and a reminder's influence on emotions improved with age and that children's understanding of the external causes of emotion related to ToM understanding. Practice or Policy: Findings suggest that programs that seek to promote children's socioemotional awareness could benefit from encouraging the development of children's understanding of the external causes of emotions to improve overall social cognition. (Contains 1 figure, 5 tables, and 2 footnotes.)