Aims: Cognitive therapies are increasingly being offered by clinical psychologists to people with intellectual disabilities. This paper reviews some of the factors that influence people's readiness to engage in cognitive therapy. Literature review: Limited verbal ability, psychological-mindedness (particularly in relation to the understanding of emotions and the mediating role of cognitions), and self-efficacy, are all likely to present significant barriers. There may also be motivational barriers to treatment, including the functionality of some psychological presentations, maladaptive beliefs promoting resistance to change, the intellectually challenging nature of cognitive therapy, and external factors such as inappropriate settings. Engagement with therapy can be promoted by involving carers to support the therapy, but carers may themselves display a range of limitations of ability and motivation similar to those displayed by clients, which need to be recognized, and where possible addressed, in order for their involvement to be effective. Recommendations: If barriers to treatment are recognized, significant steps can be taken to increase accessibility. In addition to simplifying the delivery of therapy, there is also scope to simplify the model; this point is illustrated by case examples, and some principles for formalizing modifications to standard procedures are suggested. As barriers to treatment can often be surmounted, a decision whether or not to offer cognitive therapy should be derived from a comprehensive formulation, and should never be based solely on a client's performance on tests of cognitive ability.