The bullying phenomenon has been simplified and studied primarily from a psychological perspective. In this study, the phenomenon of bullying was examined by analyzing the joint influence of sociocultural factors such as gender stereotypes, sexism, and attitudes toward sexual and cultural diversity on bullying participation as a bully and a bully follower. Participants were 1,165 Spanish and Portuguese adolescents with a mean age of 14.64 years. The hierarchical linear regression model reveals that bullies are less expressive and more instrumental, they hold more hostile sexist and less benevolent sexist attitudes, more negative attitudes toward homosexuality and more positive ones toward lesbianism, as well as more negative behavior toward gender nonconforming people, and more negative attitudes toward cultural diversity. With the exception of expressiveness and negative attitudes toward cultural diversity, these variables also explain participation as a bully follower. Implications for the development of educational policies and practices of bullying prevention are discussed.