Misophonia is a condition of unknown cause characterized by atypically intense negative physiological and emotional reactions to hearing certain sounds – most often those associated with oral functions. Individuals with misophonia often report high levels of psychological distress and avoidance behaviours that seriously compromise their occupational and social functioning. As of yet, no effective treatment of misophonia has been identified, and health care providers often struggle when they encounter clients who have it. This case report describes the assessment, case formulation, and treatment of a client with misophonia using cognitive behavioural therapy (CBT), and serves as an initial contribution to the evidence base for the efficacy of CBT in the treatment of misophonia.