In linguistics, linguistic competence is the system of unconscious knowledge that one knows when they know a language. It is distinguished from linguistic performance, which includes all other factors that allow one to use one's language in practice.

In approaches to linguistics which adopt this distinction, competence would normally be considered responsible for the fact that "I like ice cream" is a possible sentence of English, the particular proposition that it denotes, and the particular sequence of phones that it consists of. Performance, on the other hand, would be responsible for the real-time processing required to produce or comprehend it, for the particular role it plays in a discourse, and for the particular sound wave one might produce while uttering it.

The distinction is widely adopted in formal linguistics, where competence and performance are typically studied independently. However, it is not used in other approaches including functional linguistics and cognitive linguistics, and it has been criticized in particular for turning performance into a wastebasket for hard-to-handle phenomena.