Social exclusion amongst rural-dwelling older adults and the role of the diversity of people and places in mediating the construction of that exclusion has not been adequately investigated or conceptualised in the international literature. Consequently, how ageing in a rural community can function to disadvantage or protect older people remains poorly understood. With the aim of advancing conceptual understanding on rural old-age social exclusion, this article explores how exclusion is manifest in the lifecourse experiences of rural-dwelling older adults and the role of mediating factors in the construction of exclusion in different kinds of rural places. The analysis draws on ten rural case-study sites across Ireland and Northern Ireland, encompassing five kinds of rural communities: dispersed rural; remote rural; island rural; village rural; and near-urban rural. Data come from 106 interviews with older people ranging in age from 59 to 93 years. Rural old-age social exclusion is confirmed as a multi-dimensional construct, involving: social relations; service infrastructure; transport and mobility; safety, security and crime; and financial and material resources. This analysis demonstrates that social exclusion for rural-dwelling older people is multi-layered, and its prevalence and form is shaped by four mediating factors: individual capacities; lifecourse trajectories; place; and macro-economic forces. The findings are used to present a conceptual framework that emphasises the role of mediating forces on rural old-age social exclusion.