This study examined the role of attitudes against bullying and perceived peer pressure for intervention in explaining defending the victim and passive bystanding behavior in bullying. Participants were 1031 school-age children from two culturally diverse settings, namely Italy and Singapore, which are similar on several dimensions (e.g., quality of life, child welfare) but dramatically differ on other aspects, such as individualism—collectivism orientation. Multilevel analyses showed that country and participants' gender moderated the relations between individual predictors and behavior during bullying episodes. In particular, although individual attitudes were a stronger predictor of Italian students'—especially girls'—behavior, perceived peer expectations were more strongly associated with behavior of Singaporean participants. This study contributes to the literature by being the first to provide data analyzing the association between defending and passive bystanding behavior and different correlates using a cross-cultural approach.