Background: Information regarding the common-daily support needs of older people with intellectual disabilities remains scarce, despite the necessity of such knowledge to the provision of adequate support. This exploratory study aims to identify the most important support needs. Method: A mixed-method design was conducted, in which 11 semi-structured interviews were held with psychologists to gain insight into the support needs of older people with intellectual disabilities. Results: The data provide an overview of the support needs of older people with intellectual disabilities in all quality-of-life (QoL) domains. Physical well-being, emotional well-being, interpersonal relationships and self-determination were identified as the most important domains for older people with intellectual disabilities. Conclusions: The findings of this study may guide the development of a specific training for support staff and constitute a valuable contribution to raising awareness among support staff concerning the broad range of support needs existing among older people with intellectual disabilities.