This study investigated the relationship between online and real-world aggressive behavior among primary school students as well as the effects of an online rational emotive curriculum on reducing the tendency of students to display aggression online and in the real-world. We developed an online information literacy course integrated with rational emotive behavior therapy (REBT) to reduce aggressive behavior, using online incidents of hostility as instructional material. An experiment was conducted on four intact Grade 5 classes comprising 67 students using rational emotive curriculum. Control groups comprising 63 students took the same course without the rational emotive curriculum. All of the students participated in one class per week for six weeks consecutively. Our results indicated: (a) a moderate correlation between online and real-world aggressive behavior among primary school students; and (b) the online rational emotive curriculum had a significant effect alleviating aggressive behavior among students with strong hostile tendencies. (Contains 7 tables.)