Conflict in a workgroup turns into harassment if a group member is persistently confronted with negative acts with few possibilities to retaliate. Cross-national differences in such intragroup harassment are considerable but wait to be understood. In this study, survey data from 44,836 employees in 44 countries revealed that a cultural in-group orientation was associated with lower employee harassment. In addition, and in agreement with Van de Vliert's climato-economic theory of culture, workforces reported more harassment in poorer countries with more demanding climates of colder-than-temperate winters, hotter-than-temperate summers, or both. Finally, it was found that the impact of climato-economic hardships on harassment suppressed the impact of cultural in-group orientation on harassment. Using the regression equation obtained for the sample of 44 countries, national levels of employee harassment for a broader pool of 103 countries were estimated and scrutinized for their validity for future research. Data from the World Values Surveys were used to validate the estimations. The results provide the basis for a further hypothesis, that employee harassment is more prevalent in countries with either survival or self-expression cultures than in countries with cultures that are intermediate between those two extremes. The results have implications for prevention and remedial measures.