Background: There is increasing interest in the provision of cognitive behaviour therapy (CBT) to people with intellectual disabilities. A small number of studies have begun to address therapy process issues. Aims: The aim of this paper is to contribute to process research through the development of a taxonomy of question types for use in analysing therapy interactions in CBT for people with intellectual disabilities. Method: A taxonomy of CBT question types was adapted and applied to the transcriptions of session 4 and 9 of 15 CBT therapy dyads. Results: The taxonomy was reliably applied to the data. Therapists used significantly more questions in session 4 than in session 9, therapists used fewer questions in the final quarter of all sessions, and therapists used more questions with people with higher IQ scores in session 4 but not in session 9. Conclusions: The taxonomy of questions is reliable and may be used in future studies of CBT therapy process with people with intellectual disabilities.