The act of criminalising conduct has been understood by many theorists as a form of communication. This paper proposes a model, based on speech-act theory, for understanding how that act of communication works. In particular, it focuses on analysing how and where wrongfulness can appear in this speech-act, if one were to argue, as many theorists do, that part of what is being communicated through criminalisation is the wrongfulness of the target conduct. I argue that the act of criminalisation is (...) best understood as an indirect speech-act, which both asserts and declares normative facts, the utterance of which makes it the case that a conduct is now criminalised. Within this speech-act, wrongfulness can appear as an implicit assertion of the wrongness of the conduct, which has to be inferred by hearers from the context of utterance. The paper then briefly discusses the upshots of this model, mainly that it allows a clearer picture of how criminalisation conveys meanings, as well as leaving open the question as to whether it makes sense to think that the wrongfulness being conveyed is specifically of a moral kind. (shrink)