Substance use among older adults in South Asia is a growing yet underexplored public health issue. It is posing greater challenges with the increase in the ageing population and evolving social and cultural norms. Tobacco, alcohol, areca nut, and prescription medications are among the commonly used substances. Meanwhile, illicit drug use is also reported in some regions. Contributing factors include easy accessibility to substances, chronic pain, insomnia, loneliness, and mental health issues. Cultural practices and norms regarding substances are key factors influencing their use. Limitations concerning poor awareness and help-seeking, financial adversities, frail health, and social stigma are important challenges to availing treatment and care. Inadequate research further hinders efforts to develop effective prevention and treatment strategies. Despite the major health implications of substance use and a growing need for healthcare, the facilities in South Asia often lack age-sensitive, integrated interventions to address this issue. There is a need for a comprehensive approach to managing substance use disorders in older adults, incorporating culturally adapted education, building community support systems, and providing accessible healthcare services.