<p>This scoping review maps qualitative research on user participation in social housing work and practices for people with mental health and/or substance use challenges in Denmark, Norway, and Sweden. User participation has become a central value in Nordic welfare states, promoted to strengthen empowerment, improving services, and reinforce democratic ideals. While Nordic countries share features, Denmark, Norway, and Sweden represent the core of the Social Democratic welfare regime, providing a coherent basis for comparative analysis of housing policies and practices. Drawing on studies published between 2015 and 2025, this review identifies how user participation is conceptualized and enacted across individual, service, and system levels. Eleven included studies show that user participation extends beyond formal service plans and is embedded in everyday relationships, residents’ degree of control, and opportunities for co-production. Practices fostering meaningful user participation include relational continuity, flexible routines, recovery- and citizenship-oriented perspectives, and collaboration with user organizations. Yet user participation is limited by organizational mandates, professional ideas of “suitable housing”, and structural pressures. Ongoing tensions between care and control, plans and lived realities, and provision and user participation shape frontline practice. Across contexts, people with mental health and/or substance use challenges remain stigmatized and marginalized, often excluded from genuine influence over housing and services. The findings underscore the need for approaches that translate universalist welfare principles and human rights commitments into concrete practices supporting housing stability, quality of life, and social inclusion.</p>