A theory of grammar developed by Charles Fillmore, Paul Kay and their collaborators.

While this theory is broadly generative in orientation, it sets the scene for the development of cognitively realistic theories of construction grammar which adopted the central thesis of Fillmore and Kay's approach. This thesis is the position that grammar can be modeled in terms of constructions rather than 'words and rules'. Thus Fillmore and Kay developed the symbolic thesis as the basis for a theory of grammar. In particular, Construction Grammar is motivated by the fact that certain complex grammatical constructions, in particular idiomatic expressions such as kick the bucket or throw in the towel, have meaning that cannot be predicted on the basis of their sub-parts and might therefore be 'stored whole' rather than 'built from scratch'. Fillmore and Kay authored two classic construction grammar papers which presented case studies of the let alone construction and the What's X doing Y construction.

One of the notable features of construction grammar is that this model is 'monostratal': containing only one level of syntactic representation rather than a sequence of structures linked by transformations: a feature that characterizes theories of grammar in formal linguistics such as generative models of grammar. Furthermore, the representations in construction grammar contain not only syntactic information but also semantic information relating to argument structure as well as pragmatic information.