We explored how investments in housing for vulnerable populations (including those experiencing homelessness) are described as leading to cost containment for the health, justice, and social service systems; the nature of any costs and benefits; and variations by housing type and over time. A structured search of peer-reviewed academic research focused on the core concepts of economic benefit, public housing programs, and vulnerable populations. Findings from 42 articles reporting on cost containment specific to health, justice, and social service systems at the municipal, regional, and/or state/provincial level were synthesized. Most of the studies focused on supportive housing interventions, targeted adults (mainly men) experiencing chronic homelessness in the USA, and reported results over 1-5 years. Approximately half of the articles reported on the costs required to house vulnerable populations. About half reported on funding sources, which is critical information for leadership decisions in cost containment for supportive housing. Most of the studies assessing program cost or cost-effectiveness reported a reduction in service costs and/or greater cost-effectiveness. Studies mostly reported impacts on health services, with hospital/inpatient care and emergency service use typically decreasing across the intervention types. All the studies that assessed cost impacts on the justice system reported a decrease in expenditures. Housing vulnerable populations was also found to decrease shelter service use and engagement with the foster care/welfare systems. Housing interventions may offer cost-savings in the short- and medium-term, with a limited evidence base also demonstrating long term benefit.