BACKGROUND: Health inequalities have widened globally over the past decade, disproportionately affecting socially excluded populations broadly defined as 'inclusion health groups'. These groups, including people experiencing homelessness, migrants, sex workers, people with substance use disorders, victims of modern slavery, and those in contact with the justice system, face compounded negative health consequences often exacerbated by stigma. This scoping review aimed to examine qualitative literature exploring how stigma impacts the physical and mental health of inclusion health groups. Building on the work of Link and Phelan, Tyler, and Hatzenbuehler, this review situates stigma as a relational and structural process that operates through power, policy, and institutions to shape health outcomes among inclusion health populations.

METHODS: The review focused on identifying how stigma is conceptualised across inclusion health groups and how it functions as a shared mechanism influencing health, health behaviour, and access to care. Following the PRISMA-ScR framework, we searched Scopus, OVID Medline, and PsycINFO for qualitative studies published between 01/01/2015 and 15/03/2025. Titles, abstracts, and full texts were screened, resulting in 28 articles included for analysis.

RESULTS: Stigma was consistently identified as a barrier to healthcare access, leading to delayed treatment and worsening physical and mental health outcomes for inclusion health groups. The literature disproportionately focuses on people who use drugs, with limited research addressing other inclusion health groups, highlighting significant gaps in the field. Furthermore, existing conceptualisations of stigma frequently neglect its structural determinants, risking reinforcement of individualised explanations for poor health rather than addressing systemic drivers of inequality.

CONCLUSIONS: This review demonstrates that stigma contributes to health inequalities by limiting healthcare access and shaping negative health outcomes. There is an urgent need for research that investigates stigma's long-term health effects and moves beyond individual-level interventions to address broader structural forces perpetuating health inequalities. Future work should more explicitly engage with the concept of structural and political stigma, recognising that public health research must interrogate the upstream determinants, such as policy, governance, and social organisation, that sustain exclusion and health inequity.