Background <p>Housing insecurity, or the inability to afford or maintain residence in a safe and quality place, is a barrier to accessing and staying in substance use treatment and/or recovery support services. There is a gap in knowledge in how housing insecurity influences substance use disorder (SUD) prevalence, and the role housing security plays in SUD treatment initiation and retention. The HEALing Communities Study (HCS) is a large multisite trial aiming to reduce overdose risk through the implementation of evidence-based interventions delivered by community coalitions to reduce overdose deaths among 67 counties in 4 states. This study explored diverse perspectives of HCS community coalition members on housing systems for populations with SUD to better understand how housing insecurity attenuates SUD prevalence and initiation or retention in various drug treatment services.</p> Methods <p>The aim of this study was to explore various mechanisms at multiple levels through which housing insecurity adversely affects individuals with SUD. Semi-structured key informant interviews (<i>n</i> = 85) were conduct with HCS community coalition members in New York State from 2019 to 2020. The transcripts were coded using the PRISM/RE-AIM framework and further subcoded with the following five themes: 1) cost (housing affordability); 2) conditions (housing quality); 3) consistency (residential stability); 4) context (neighborhood opportunity); and 5) considerations (unique aspects affecting substance use-related populations).</p> Results <p>Findings include housing insecurity driven by cycles of poverty or poor economic reality in NY counties, substandard or poor-quality housing, experiences of stigma or social isolation within the home, a lack of transitional housing for individuals exiting the criminal legal system, housing insecurity associated with a return to use or overdose, neighborhood challenges such as accompanying transportation or food insecurity, or environmental triggers to return to use, and challenges associated with housing insecurity for SUD treatment, such as missed appointments.</p> Conclusions <p>The results suggest that structural housing interventions are needed to improve the health and quality of life of individuals with SUD directly and that they may also strengthen the effectiveness and sustainability of other interventions with this population. Future research can explore the community co-design of innovative solutions across the continuum of housing security.</p> ClinicalTrials.gov identifier <p>NCT04111939</p>