Background <p>Social frailty and reduced functional ability are major challenges among older adults in urban slums, yet the mechanisms linking these factors remain poorly understood. Social capital may buffer the effects of social frailty, but evidence is limited in urban slums context. The protocol study hypothesized that higher social capital is associated with lower social frailty and better functional ability among older adults.</p> Methods <p>This protocol employs a convergent-parallel mixed-methods design. The quantitative phase will assess social frailty, social capital, and functional ability (Activities of Daily Living, Instrumental ADL, hand grip strength) among older adults. The qualitative phase will involve in-depth interviews with older adults and their caregivers to explore how older adults living in urban slum settings describe their social relations, social networks, and lived experiences of ageing, and how these networks and social support systems influence their daily activities, wellbeing, and functional independence. Quantitative and qualitative data will be analyzed separately and then integrated to identify pathways through which social capital influence’s functional ability.</p> Discussion <p>The study will provide insights into how social resources and relationships support functional independence in marginalized older adults. Findings will inform development of context-sensitive strategies and interventions aimed at enhancing social support, promoting resilience, and improving wellbeing in urban slum populations.</p>