Background The purpose of this study was to explore the barriers and facilitators healthcare professionals experience when managing type 2 diabetes in people with severe mental illness (SMI). Methods A qualitative semi-structured interview approach was employed. Questions were structured according to the Theoretical Domains Framework (TDF), which outlines 14 domains that can act as barriers and facilitators to changing behaviour. Interviews were audio-recorded and transcribed verbatim. The data were coded according to the 14 domains of the TDF, belief statements were created within each domain and the most relevant belief statements within each domain identified through a consensus approach. Analyses were conducted by two researchers, and d...