Individual differences in emotionality and regulation are central to conceptions of temperament and personality. In this article, conceptions of emotionality and regulation and ways in which they predict social functioning are examined. Linear (including additive) and nonlinear effects are reviewed. In addition, data on mediational and moderational relations from a longitudinal study are presented. The effects of attention regulation on social functioning were mediated by resiliency, and this relation was moderated by negative emotionality at the first, but not second, assessment. Negative emotionality moderated the relation of behavior regulation to socially appropriate/prosocial behavior. These results highlight the importance of examining different types of regulation and the ways in which dispositional characteristics interact in predicting social outcomes.