Health-related stigma can shape healthcare inequality through more than overt discrimination. Anticipated rejection, internalized devaluation, stigmatizing clinical encounters, institutional practices, and structurally unequal conditions may influence psychological well-being, help-seeking, access, communication, diagnostic processes, treatment engagement, and continuity of care. These processes are often studied separately, limiting understanding of how stigma operates across levels. This systematic review was structured according to PRISMA 2020 reporting principles and used a prespecified 2017–2026 evidence window. Evidence was classified by stigma level, healthcare-inequality outcome, study design, population, setting, and intervention target. Because clinical, qualitative, observational, experimental, implementation, and review evidence addressed heterogeneous constructs and outcomes, synthesis emphasized structured comparison rather than unsupported quantitative pooling. Numerical review-flow counts were not reconstructed where source-level retrieval and deduplication data were unavailable. The literature consistently distinguished experienced, anticipated, internalized, interpersonal, healthcare-organizational, and structural forms of stigma, although measurement practices varied substantially. Psychological consequences were most consistently documented for depressive symptoms, distress, identity threat, and internalized stigma. Healthcare consequences included delayed or avoided care, impaired trust, burdens associated with disclosure and identity management, stigmatizing documentation, poorer communication, and barriers embedded in organizational or structural conditions. Effects were strongly conditioned by population, illness context, visibility of the stigmatized characteristic, social support, institutional arrangements, and intersecting disadvantage. Health-related stigma is better understood as a multilevel inequality process than as a single individual exposure. Its consequences can emerge through psychological burden and through constrained healthcare opportunity, and these pathways may converge, diverge, or reinforce one another. Intervention strategies therefore require explicit alignment between the level at which stigma is generated and the level at which change is attempted.
