Research suggests that the relationship between school bullying and its various risk factors should be clearer among girls than boys, and should become stronger with age, as roles within the peer group stabilise. This paper tests this theory by comparing sex, school type, and bully/victim status differences in friendships and playground social interactions, using data from nine surveys in seven countries: China, England, Ireland, Italy, Japan, Portugal, and Spain. A total of approximately 48,000 children completed various translations of the Olweus Bullying Questionnaire. Small but generally consistent main effects were found for sex and school type (boys and primary pupils enjoyed playtimes more and had more friends, but were also more likely to spend playtimes alone). Larger effects were consistently found for bully/victim status (victims were significantly worse off on all the measures in all the samples where a difference was found, while bullies and neutrals did not differ consistently), but the interactions between these factors varied widely between samples and there were few consistent patterns. It is concluded that bullying is a universal phenomenon with many negative correlates for victims and few (if any) for bullies, but that there are cultural variations in the way that bullying is related to sex, age, and social support. Aggr. Behav. 30:71-83, 2004. r