Background Based on the idea of the Common Sense Model of Illness Representations by Leventhal as well as Lohaus's concepts of health and illness, a health behaviour model was designed to explain health behaviours applied by persons with intellectual disabilities (ID). The key proposal of this model is that the way someone understands the concepts of health, illness and disability influences the way they perceive themselves and what behavioural approaches to them they take. Method To test this model and explain health differences between the general population and person with ID, 230 people with ID and a comparative sample of 533 persons without ID were included in this Austrian study. Data were collected on general socio‐demographics, personal perceptions of illness and disability, perceptions of oneself and health‐related behaviours. Results Psychometric analysis of the instruments used showed that they were valid and reliable and hence can provide a valuable tool for studying health‐related issues in persons with and without ID. With respect to the testing of the suggested health model, two latent variables were defined in accordance to the theory. The general model fit was evaluated by calculating different absolute and descriptive fit indices. Most indices indicated an acceptable model fit for all samples. Conclusions This study presents the first attempt to explore the systematic differences in health behaviour between people with and without ID based on a suggested health model. Limitations of the study as well as implications for practice and future research are discussed.