As governments and service agencies across the world grapple with chronic rates of homelessness and housing instability, there is a growing need to understand the value that providing secure, stable housing brings to the lives of people who are homeless and the broader community. The complex nature of homelessness is revealed across a variety of academic fields including planning, pharmacology, urban affairs, housing policy, nutrition, psychiatry, sociology, public health, urban health, and criminology. We undertook a scoping review according to PRISMA-P (Preferred Reporting Items for Systematic Review and Meta-analysis) that mapped the breadth and scale of the evidence-base and identified themes and gaps. We identified 476 reports and after excluding duplicates and ones that did not relate to our criteria, were left with 100 studies from eight countries. Each of them identified benefits and/or changes that occurred when people experiencing homelessness or housing insecurity transitioned into a secure, stable home. Outcomes measured were distributed across a range of domains including physical and mental health, well-being, mortality rates, criminal justice interaction, service use, and cost-effectiveness. Findings varied by degree but overwhelmingly found improvements in all domains once people were permanently housed. Housing provided a foundation for people to envisage a better life and make plans for the future. As one woman who had fled a violent home was quoted as saying: “housing made everything else possible.” The research identified savings for taxpayers and the wider community once people left homelessness for the stability of a permanent home, even after factoring in the cost of housing and rental help. We found numerous gaps. For example, there was a prevalence of studies that focused on those who are visibly homeless, in particular chronically homeless men with mental illness and/or substance use issues. Much less research looked at women whose patterns of homelessness are more varied and even less at homelessness involving children and families. Women who had left domestic and family violence were investigated in a very small number of studies and sample sizes were small. Few reports undertook the complex task of quantifying and comparing cost savings. Other notable gaps were older women, older people more generally, refugees, recent migrants, veterans, Indigenous people and those with a disability.