Social-emotional learning (SEL) skill includes the ability to encode, interpret, and reason about social and emotional information. In two related studies, we examined the relationship between children's SEL skill, their ability to regulate their own behavior, and the competence of their social interactions. Study 1 included 158 typically developing children ages 4 to 14 years. Study 2 included 126 clinic-referred children ages 5 to 17 years. Findings from both studies supported the conclusion that SEL skill includes three broad factors: awareness of nonverbal cues; the ability to interpret social meaning through theory of mind, empathy, and pragmatic language; and the ability to reason about social problems. Furthermore, the better children perform on measures of SEL skill and the more their parents and teachers report that children can regulate their behavior, the more competent their social interactions. (Contains 2 figures.)