Purpose Loneliness may have different cultural meanings in different countries. This may manifest as differing levels of Social Asymmetry—the discrepancy between loneliness and social isolation. Since loneliness is thought to be low in Sweden relative to more southerly countries, we hypothesised that more number of individuals would also fall into the “discordant robust” category of Social Asymmetry, i.e. that more individuals in Sweden would have lower loneliness levels relative to social isolation than in Ireland. We also explored the clinical relevance of Social Asymmetry in both countries, by examining its association with cognitive functioning. Methods We derived Social Asymmetry metrics in two representative cohort studies: the Irish Longitudinal Study on Ageing (TILDA) and the Swedish National Study on Aging and Care in Kungsholmen (SNAC-K). Data pertaining to a dementia-free sample of 4565 Irish participants and 3042 Swedish participants, all aged over 60 years, were analysed using a multilevel modelling approach, with country as a higher-order variable. Results Contrary to the expected, more individuals in Ireland were “discordant robust” than in Sweden. We also found evidence for superior performance in global cognitive functioning among those in the “discordant robust” category relative to those in the discordant susceptible (i.e. those with higher levels of loneliness than social isolation) category, β = 0.61, p < .001, across both countries. Conclusions Irish older adults may be more robust to the impact of social isolation on loneliness than those in the Swedish cohort. Social Asymmetry was related to cognitive functioning in both countries, suggesting that Social Asymmetry is a clinically relevant construct.