Supportive housing is the foundation of an effective community mental health system. Without good quality housing and appropriate support successful community living and recovery are not possible. Ontario is fortunate in having both a mature and an expanding supportive housing system for people with serious mental illness. Nonetheless, the system faces a number of challenges. A principal challenge is lack of sufficient and appropriate options to accommodate all who require housing. A second challenge, among several others, is a lack of information to effectively manage the current stock of housing and supports and to plan for the future. The purpose of this work is to develop a foundation for planning the evolution of Ontario’s system of supportive housing and community-based supports and to make recommendations for strengthening this system. This work had three goals. The first goal was to propose a value-base and evidence-base for strengthening the mental health housing system. The second was to assess the gap between this proposed base and the current mental health housing system and community supports system in the province. The third goal was to make recommendations for narrowing the gap between the proposed system and the actual system and for monitoring progress in narrowing this gap.