Metaphors constitute a relevant method for both building and making sense of theories. Semiotics is not exempt from their influence, and an important range of semiotic theories depends on metaphors to be meaningful. In this paper, we wish to examine the place of theory-constitutive metaphors considering the interaction view and the extent to which some areas of semiotics, particularly, the semiotics of culture and biosemiotics, are enriched by having metaphors dominate the way we think about them. The intention of the paper is not to document the different metaphors that have built semiotic theory, but rather to observe through a number of examples that semiotic research contains theory-building metaphors and that these are productive means of developing semiotic thinking further, with the caveat that theory change can be unexpected based on how we build metaphors for our theories.