Background: Self-management of health includes people with intellectual and developmental disabilities (IDD) playing a key role in health management in collaborating with healthcare professionals. Methods: This study analysed data from Personal Outcome Measures® surveys (n = 1,341) to explore self-management of health. We had the following research questions: Who is most likely to be supported to self-manage their health? How does being supported to self-manage impact different areas of health? and How does being supported to self-manage impact other health-related organizational supports? Results: Findings revealed the impact of self-management of health can be wide-ranging, regardless of impairment severity. When supported to self-manage their health, healthcare professionals were more likely to address healthcare issues, and interventions were more likely to be effective. Conclusions: Self-management represents a paradigm shift for people with IDD because it transforms people from passive recipients to active directors of their health.