In linguistics and grammar, a pronoun is a word that substitutes for a noun or noun phrase. It is a particular case of a pro-form.

Pronouns have traditionally been regarded as one of the parts of speech, but some modern theorists would not consider them to form a single class, in view of the variety of functions they perform. Subtypes include personal pronouns, reflexive and reciprocal pronouns, possessive pronouns, demonstrative pronouns, relative pronouns, interrogative pronouns, and indefinite pronouns.