Objectives: To carry out a preliminary exploration and measurement of therapy expectancy in adults with intellectual disabilities through the development and psychometric evaluation of the therapy expectation measure (TEAM). Design: The initial scale development phase combined top-down theory-driven and bottom-up data-driven processes to identify TEAM items and format. The subsequent scale evaluation phase piloted the TEAM and used correlational analyses to evaluate reliability and validity. Method: Six adults with intellectual disabilities took part in semi-structured interviews about therapy expectancy and motivation to identify TEAM items. A further 22 participants piloted the measure for initial psychometric evaluation. Results: Preliminary psychometric evaluation confirmed that the TEAM has acceptable test-retest reliability and internal consistency. Assessment of construct validity found a strong and positive relationship with a measure of general self-efficacy. Client expectations of therapy were largely positive and congruent with therapy as a goal-oriented process in which they will be an active participant. However, a number of individuals were unclear about the reason for referral and felt a low level of involvement in the process. Client and carer perceptions of referral understanding were significantly different. Conclusions: The TEAM may help clinicians to identify potential barriers to engagement in therapy and find ways of enhancing the therapeutic experience of adults with an intellectual disability. Further psychometric evaluation of the TEAMM with larger samples is required to confirm the factorial structure of the scale and enhance its clinical utility.