Pragmatic disorders pose a barrier to effective communication in a significant number of children and adults. For nearly forty years, clinical investigators have attempted to characterize these disorders. This chapter examines the state of the art in clinical pragmatics, a subdiscipline of pragmatics that studies pragmatic disorders. The findings of recent empirical research in a range of clinical populations are reviewed. They include developmental pragmatic disorders found in autistic spectrum disorders, specific language impairment, intellectual disability and the emotional and behavioural disorders, as well as acquired pragmatic disorders in adults with left- or right-hemisphere damage, traumatic brain injury, schizophrenia, and the dementias. Techniques used by clinicians to assess and treat pragmatic disorders are addressed. In recent years, theoretical frameworks with a cognitive orientation have increasingly been used to explain pragmatic disorders. Two such frameworks—relevance theory and theory of mind—will be examined in this essay.