Objective: Despite clinical observation that stroke survivors frequently experience loneliness, there is no large-scale empirical evidence to support this observation. Therefore, the primary objective of this research was to provide the first large-scale and comprehensive estimate of loneliness in the stroke survivor population. Method: To address this issue, we completed two pre-registered analyses of a nationally representative annual survey (N> 21 000). A two-phase approach was adopted combining both exploratory (Study 1) and confirmatory (Study 2) phases. The benefit of such an approach is that replication is built into the design, which considerably strengthens the inferences that can be made. Results: Across two separate cohorts, the results consistently showed that human stroke survivors report higher levels of loneliness compared to healthy individuals, and this relationship could not be accounted for by demographic factors (e.g., age, sex) or objective measures of social isolation (e.g., marital status, number of household members). Conclusions: These findings demonstrate that elevated levels of loneliness post-stroke are robust in that they replicate in large nationally representative samples and cannot be reduced to objective measures of social isolation. The work has clinical and societal relevance by suggesting that loneliness post-stroke is unlikely to be adequately “treated” if only the quantity and not the quality of social experiences are considered.