Research within constructional approaches to language has begun to develop a framework for modelling diachronic variation, but the precise relationship between diachronic construction grammar and grammaticalization has yet to be fully worked out (Noël 2007). The article includes discussion of some central issues in construction grammar which are of significant relevance to researchers interested in grammaticalization and lexicalization, with suggestions for some of the ways in which key topics in grammaticalization research – such as unidirectionality, reanalysis and analogy – might be explained using a constructional model. In order to illustrate this thesis, I draw on a range of data from the history of English (particularly, quantifiers and degree modifiers, composite predicates and possessives).