Background: There is a paucity of literature detailing cognitive-behavioural therapy (CBT) for psychosis in people with intellectual disability. Of the available literature, only two case studies involve people with command hallucinations and these do not address specific issues of intervention indicated in the wider literature for this type of presentation. Methods: The present paper reports a case study documenting the successful application of CBT targeting the treatment of command hallucinations for mild intellectual disability. Results: A range of measures (including positive and negative syndrome scale, beliefs about voices questionnaire and psychotic symptom rating scale for auditory hallucinations) collected at pre- and post-intervention indicates successful reduction in positive symptoms, with 3- and 6-month follow-up data indicating maintenance of improvements. Critically, positive clinical changes in core beliefs regarding the power of the hallucinatory voice are also observed. Conclusions: Cognitive-behavioural therapy for command hallucinations can be successfully adapted and applied to people with a mild disability.