Aim: To better describe the role and timing of palliative care in supporting persons with intellectual disabilities and advanced dementia (AD). Background: Specialist palliative care providers have focused mostly on people with cancers. Working with persons with intellectual disabilities and AD offers opportunities to expand such palliative care to other populations and disease conditions and to better understand the timing and role of palliative care delivery. Methods: Thirteen focus group interviews were held involving staff in six intellectual disability services and one specialist palliative care provider in Ireland. A qualitative descriptive approach was taken to analysis. Results: Specialist palliative care staff recognized that person-centred care delivered in intellectual disability services was consistent with palliative approaches, but staff in intellectual disability services did not consider advanced dementia care as "palliative care". Both groups were unsure about the role of palliative care at early stage of dementia but appreciated specialist palliative care contributions in addressing pain and symptom management challenges. Conclusions: Successful extension of palliative care principles, philosophy and services to persons with intellectual disabilities and AD will require in-depth understanding of prevailing care philosophies and agreement regarding timing and the unique contributions of specialist palliative care services.