--- - |2 Individuals with intellectual disabilities (ID) are more vulnerable to mental health difficulties than the general population, yet there are limited evidence‐based treatments available for this group. There has been a growing interest in adapting cognitive behaviour therapy (CBT) for this population; however, a framework describing how to modify cognitive challenging for a group characterized by cognitive impairment is lacking. The aim of this paper is threefold: (a) to describe how to implement cognitive challenging for adults with ID; (b) to report results from a pilot evaluation of a manualized, modified CBT‐ID programme for anxiety; and (c) to compare participants with mild versus moderate ID on post‐treatment cognitive challenging competencies. Results showed that the broad CBT‐ID programme significantly reduced anxiety in adults with ID as measured by self, informant, and clinician ratings. In addition, adults with mild but not moderate ID demonstrated competence across a range of specific cognitive challenging skills following treatment. These findings contribute to the growing evidence base for the use of CBT with people with ID. In addition, the framework described offers practitioners specific therapeutic methods to effectively challenge maladaptive thoughts that maintain anxiety in this population. - Clinical Psychology & Psychotherapy, Volume 25, Issue 5, Page 662-671, September/October 2018.