Novelty Categorization Theory (NCT) attempts to predict when people perceive events as novel and how they process novel events across different domains. It is predicted that broad mental categories reduce the perception of an event being novel via inclusion processes, whereas narrow categories increase it via exclusion processes. Furthermore, based on a ‘motive to know’, when preparing for novel events, people broaden both perception and mental categories, because to understand novel information, it is essential to integrate it into pre-existing knowledge structures that are sufficiently broad. Over time, a ‘when-novel-then-process-globally’ routine develops that is automatically elicited when novelty is encountered. Self-protective motives can, however, counteract such processing styles so that threatening novelty leads to local processing. Relations to construal level theory and action identification theory and implications for future research are discussed.