“Emotion” is a vernacular rather than a scientific concept. The experiences that are called emotions in English are a subset of a wider range of affective experiences. Categories of particular emotions similarly constitute families whose members are by no means homogeneous. As perceptions of the world and of ourselves, emotions are richly permeated by cognition. As syndromes of multiple factors, they have an event-like structure that lends itself to narrative explanation. Historical analysis of emotion(s) thus requires close attention to conceptual history and to contexts, both immediate and cultural/historical. Classicists can explore the historical contingency of “emotion” in Greek and Latin, both in the theories of the major philosophical schools and in a variety of literary texts. But emotion history now uses a much wider range of literary, documentary, visual, and material evidence. Understanding emotion is an essential aspect of many early 21st-century approaches to Classics, especially in ancient history, classical literature and rhetoric, and ancient philosophy, just as the visual and physical remains of the classical world are rich in emotional implications and deeply entwined with the representation, performance, and pragmatics of ancient emotion.