In British Columbia, approximately 11,750 adults with severe addictions and/or mental illness are homeless. People who live with mental illness or the ill social or physical effect of substance use represent a sub population of people who experience homelessness. Many factors have contributed to poverty and homelessness among people who are mentally ill and to the neglect of their physical and mental health needs. A key factor has been the policy decision to de-institutionalize mental health services in British Columbia from the hospital to the community setting. Individuals living with mental illness were discharged from the hospital into the community, where housing is expensive and individuals have limited opportunities to earn an adequate income. Moreover, the community setting lacked the infrastructure to support and promote the health of severely mentally ill individuals. In the studied region, Assertive Community Treatment (ACT) teams have been established to work with individuals to break the cycle of homelessness, mental illness, and addiction as well as to support the improvement and maintenance of the mental and physical health of these individuals living in the community. Among the criteria for care by these regional teams is chronic homelessness caused by the barriers of mental health and addiction. In this grounded theory study, I explore how four regional ACT teams support their clients to maintain housing. In addition to examining the successes and challenges experienced by ACT team members, I consider the strengths of the team as they attempt to provide a supportive infrastructure that enables clients to maintain housing. Data were collected from four ACT teams in the region. The data collection involved two focus group discussions, three observational sessions with team members in the field, twelve one-on-one interviews, and a review of documents and reports. Data collection and analysis occurred concurrently, and guided further interviews. Through systematic analysis a theory was constructed form the data. In this study, I explore and analyze the issues that team members encounter and how they resolve them. I also take into account the beneficial outcomes of their complex work to produce a grounded theory explaining how ACT teams assist clients in maintaining housing. The knowledge gained during this study can be used to inform practice guidelines and policy development for the ACT teams. This study also contributes to the evolving body of knowledge that may strengthen provincial initiatives to break the cycle of homelessness. This work also contributes to current discussions on how to provide optimal housing support to individuals with severe mental illness and/or addiction issues. / Graduate / 0569 / 0573 / 0347 / shonalalonde@gmail.com