This article explores the role of emotions in the explanation of behavior. It first provides an overview of complexities associated with the term ‘emotion’ before discussing the link between emotions and rationality. In particular, it considers the rational choice theory of action and the notion of emotional choice, along with the impact of emotion on substantive preferences, formal preferences, beliefs and belief formation, and information-gathering. The article argues that emotions governing action should not be deemed inaccessible to analytic social-science inquiry. Even if emotions trigger actions and reactions discontinuous with prior action streams, emotions do not make the rational-actor model fail. Emotions can determine belief and urgency-based emotions can determine outcomes.