Abstract
This article focuses on the notion of interpersonal grammatical metaphor as understood in Halliday's model of systemic functional linguistics (SFL). First, the concept of grammatical metaphor as developed in SFL is reviewed and its relation to comparable concepts developed in other linguistic schools is specified. On the basis of a general semiotic- functional characterization of the interpersonal sign in terms of scoping and grounding, I will then define interpersonal grammatical metaphor as involving a doubling of semiosis, viz. a doubling of scoping in its structural-realizational dimension, and a doubling of grounding in its semantic-functional dimension.