In the current climate of migration and globalization, personality characteristics of individualsfrom different countries have received a growing interest. Previous research has establishedreliable differences in personality traits across countries. The present study extends thisresearch by examining 30 personality traits in 22 countries, based on an online survey inEnglish with large national samples (NTotal = 130,602). The instrument used was a comprehensive,open-source measure of the Five Factor Model (FFM) (IPIP-NEO-120). We postulatedthat differences in personality traits between countries would be small, labeling this aSimilarities Hypothesis. We found support for this in three stages. First, similarities acrosscountries were observed for model fits for each of the five personality trait structures. Second,within-country sex differences for the five personality traits showed similar patternsacross countries. Finally, the overall the contribution to personality traits from countries wasless than 2%. In other words, the relationship between a country and an individual's personalitytraits, however interesting, are small. We conclude that the most parsimonious explanationfor the current and past findings is a cross-country personality Similarities Hypothesis.