Background: The present study investigated staff perspectives on supporting individuals with intellectual disabilities with mental health relapse prevention. Methods: Eight staff with experience working with or supporting individuals engaged with a specialist mental health in intellectual disability (MHID) service (team member = 2, management roles = 2, nursing/social care = 4; average years' experience = 16 years, SD = 13.7) completed semi-structured interviews and thematic analysis was conducted on the resulting data. Findings: Participants held mostly positive views of MHID supports and described being actively involved in individualised and person-centred mental health supports. There was variation in awareness and recognition of relapse prevention between MHID and other (frontline) staff. Although frontline staff generally did not express explicit knowledge of relapse prevention, there was implicit staff awareness surrounding ongoing mental health supports, managing risk and coping strategies. Frontline staff also reported a lack of knowledge of the discharge process from the MHID service. Staff questioned the nature of discharge in mental health intellectual disability supports. Conclusion: This study identifies a gap in frontline staff's explicit knowledge of mental health relapse prevention, while also highlighting the importance of ongoing mental health support for individuals with intellectual disabilities.