Older people have the highest suicide rates in several countries in Latin America and the Caribbean. However, policies and prevention strategies continue to neglect social and structural factors specific to aging. In this context, ageism in health care acts as a critical barrier that affects access to and the quality and relevance of mental health care and influences the risk of suicide in old age. This article aims to analyze ageism in health as a critical social determinant of suicide risk among older adults in Latin America. It analyzes the structural, interpersonal, and internalized expressions of ageism, as well as its impact on mental health, with emphasis on the Chilean context. A thematic narrative analysis was conducted based on the scientific literature published in Spanish between 2020 and 2025 and retrieved from biomedical and regional databases. The analysis was complemented with epidemiological data, technical documents from international organizations, and current Chilean regulations on mental health, suicide prevention, and aging. Recognition of ageism as a structural determinant of suicide risk broadens the traditional biomedical approach and incorporates political, cultural, and social dimensions into the prevention of suicide in old age. The article proposes guidelines for public policies, health programs, and professional training with a focus on rights, critical gerontology, and public health, aimed at strengthening relevant and sustained prevention responses for older adults in Chile and Latin America.