This chapter describes the Pathways Housing First (PHF) model. This program pioneered the practice of offering choices to individuals with co-occurring psychiatric and addiction diagnoses including the option to move directly from homelessness into a place of their own with supports. Pathways offered housing as a right, not something that must be earned through participating in psychiatric treatment or attaining a period of sobriety. Intensive treatment and support services are provided using community-based multidisciplinary teams that are mobile and make home visits. The program’s philosophy is guided by principles of self-determination and empowerment, and interventions are primarily directed by the service user. Participants are not discharged from the program if they relapse or if they are evicted from their housing; the support team services are continuous and assist with rehousing. The Pathways Housing First (PHF) program represents a 180-degree turn from traditional supportive housing or other group home programs serving this population which typically use a treatment-first approach and require participation in psychiatric treatment and a period of sobriety as a prerequisites for obtaining and maintaining housing. Research studies are presented comparing Housing First to Treatment First programs on measures of housing stability, quality of life, and cost-effectiveness. Results of these studies built an evidence base that influenced policy makers to advocate for implementing the Pathways Housing First model to address homelessness for individuals with complex needs which has led to the programs’ dissemination across the United States, Canada, and Europe.