In linguistics, deixis (, ) is the use of general words and phrases to refer to a specific time, place, or person in context, e.g., the words tomorrow, there, and they. Words are deictic if their semantic meaning is fixed but their denoted meaning varies depending on time and/or place. Words or phrases that require contextual information to be fully understood—for example, English pronouns—are deictic. Deixis is closely related to anaphora. Although this article deals primarily with deixis in spoken language, the concept is sometimes applied to written language, gestures, and communication media as well. In linguistic anthropology, deixis is treated as a particular subclass of the more general semiotic phenomenon of indexicality, a sign "pointing to" some aspect of its context of occurrence.

Although this article draws examples primarily from English, deixis is believed to be a feature (to some degree) of all natural languages. The term's origin is Ancient Greek: δεῖξις, romanized: deixis, lit. 'display, demonstration, or reference', the meaning point of reference in contemporary linguistics having been taken over from Chrysippus.