Background: The Self-Regulation Model (SRM) has been presented as a framework for assessing the perceptions people hold about their mental health problem. Currently no direct attempts have been made to assess the association between illness perceptions and engagement in psychosis. Engagement is an important issue for health professionals providing support to people with psychosis; therefore, research demonstrating a link between illness perceptions and engagement may enable targeted interventions to facilitate engagement and enhance outcome. Aim: To assess whether beliefs about mental health are associated with self-perceptions of engagement in people with psychosis. Method: Participants with psychosis completed two questionnaires; beliefs about mental health and self-perceptions of engagement with mental health services. Results: A belief that the mental health difficulty has fewer negative consequences, increased perceptions of personal ability to control the mental health difficulty, a belief that treatment is helpful in controlling symptoms and a more coherent understanding of the mental health difficulty were all associated with higher self-perception engagement scores. Multivariate analyses indicated that a more coherent understanding and a belief that treatment is helpful were the strongest and most consistent predictors of higher self-perception engagement scores. However, the direction of the associations cannot be established. Conclusions: This study suggests that the SRM is a promising model for mental health problems and that beliefs about mental health are associated with self-perceptions of engagement in people with psychosis. The importance of further intervention-based research studies that examines causality is highlighted.