Background: Poor diet is a contributing factor to the high rates of obesity and related comorbidities in people with severe mental illness, and dietary change is a key treatment strategy. Providing healthy lifestyle interventions is a recognised role for occupational therapists. However, the existing literature fails to elucidate boundaries of this role. To begin to address this gap in the literature, this study explored the attitudes, actions and beliefs of mental health occupational therapists about providing diet-related interventions. Methods: Semi-structured interviews were conducted with mental health occupational therapists working in one Area Health Service in New South Wales. Purposive sampling was used. Data were analysed using Constructivist Grounded Theory methods, where meaning is co-constructed by, and the theory ultimately grounded in the experiences of, the participant and researcher. Results: The participants felt confident providing clients with interventions to promote diet-related skill development and providing general healthy eating education to support this development. However, they were not comfortable providing clients with specific dietary advice. Participants identified a need for further training and support to enhance their effectiveness in providing healthy eating education and highlighted the need for more dietitians in mental health services. Conclusions: The occupational therapists in this study identified clear boundaries of their role in providing diet-related interventions for people with severe mental illness. Suggestions for improvement in this area included further training for occupational therapists as well as increased access to dietitians for those services that lie outside the occupational therapy role. Â© 2012 The Authors Australian Occupational Therapy Journal Â© 2012 Occupational Therapy Australia.