This article presents housing policy and practice recommendations for enhancing the coordination of housing, health, and social care supports for individuals leaving institutional settings. Our recommendations are derived from empirical research conducted in Australia's two most populous states (Victoria and New South Wales) between October 2019 and March 2021 among people leaving residential treatment for mental health and/or alcohol and other drug (AOD) use issues. The period immediately following discharge from these settings is known to involve significant risk of housing insecurity, particularly for vulnerable individuals with complex health and social care needs. In conducting this research, our goals were to identify models of best practice in discharge and transition planning, and to propose strategies for enhancing coordination between residential treatment providers and key social and housing support services to mitigate the risk of homelessness for individuals leaving these settings. This article presents key research findings and recommendations for improving service coordination and transition planning across diverse institutional settings.