A theory of dynamic meaning construction developed in particular by Gilles Fauconnier and extended in the work of Seana Coulson, Barbara Dancygier, Eve Sweetser and others.

Mental spaces theory also forms the basis for blending theory. The central insight of mental spaces theory is that when we think and speak, we set up mental spaces.

A mental space serves to recruit temporary structure from the local discourse context as well as recruiting structure from long-term memory via a process known as schema induction. As talk unfolds and thought proceeds, mental spaces proliferate, with new mental spaces being formed relative to others. This gives rise to a mental spaces lattice. Language provides conventional prompts for the formation of a given mental space, but mental space construction and the formation of a mental spaces lattice is subject to non-linguistic cognitive principles, especially the access principle and the optimization principle.

Mental spaces theory arose as an attempt to account for long-standing problems in philosophy of language.

In particular, mental spaces theory sought to account for various problems of linguistic reference. By proposing that discourse is partitioned into distinct mental spaces which contain counterparts and connectors holding between them, mental spaces theory provided an elegant solution to issues which had previously appeared intractable.