This paper investigates how horizontal and vertical individualism and collectivism predict self-report loneliness in addition to the variance accounted for by age and sex in 28 countries (N = 8,345). Horizontal and vertical aspects of individualism and collectivism had small but significant contributions to predicting loneliness. Horizontal-collectivism (for 19 country samples) and, to a lesser extent, horizontal-individualism (for seven country samples), significantly predicted lower loneliness scores. Vertical-individualism (for 16 country samples), and to a lesser extent, vertical-collectivism (for six country samples), predicted feeling more loneliness among our participants. Adjusted R2 values suggested that between 0.6% and 27.7% of self-report loneliness was predicted. These results suggest that those who value egalitarian social relations also tend to report being less lonely whereas those who value individuality and competitiveness endorse the loneliness items more. These results are of importance to those investigating and helping lonely individuals by appreciating the influence of perceived culture.@en