Mental health is a fundamental dimension of overall health and social well-being; however, its distribution remains profoundly unequal due to structural social determinants that disproportionately affect at-risk populations. This study aimed to analyze how social vulnerabilities influence mental health outcomes in at-risk groups and to identify comprehensive and integrated care strategies capable of reducing mental health inequities. A narrative literature review was conducted using the PubMed, SciELO, and LILACS databases, combining controlled descriptors and free-text terms in Portuguese, English, and Spanish. Studies published within the last five years were included if they addressed mental health outcomes among socially vulnerable populations and examined community-based or integrated care strategies; editorials, opinion papers, duplicates, and studies lacking methodological rigor were excluded. The findings indicate that socioeconomic deprivation, discrimination, violence, housing instability, and unemployment are strongly associated with higher prevalence of depression, anxiety, trauma-related disorders, and substance misuse. The concept of cumulative risk emerged as central, demonstrating how overlapping vulnerabilities intensify psychological distress over time. Persistent systemic barriers, including economic and geographic obstacles, service fragmentation, institutional stigma, insufficient professional training, and policy discontinuities, continue to limit effective and sustained access to care. The review highlights that community-based services, primary care integration, intersectoral policies, trauma-informed practices, culturally responsive interventions, psychosocial rehabilitation, peer support, and digital health strategies are promising approaches for reducing inequities. Evidence suggests that integrated, person-centered, and rights-based models are more effective in addressing the structural roots of mental suffering. Reducing mental health inequities therefore requires sustained public investment, intersectoral coordination, and structural transformation grounded in social justice principles.