A two-part screening procedure was used to assess school-age children's experience with bullying. In the first part 16,799 students (8,195 girls, 8,604 boys) in grades 4 to 12 were provided with a definition of bullying and then asked about their experiences using two general questions from the Olweus Bully/Victim Questionnaire (1996). In the second part, students were asked about their experiences with specific types of bullying: physical, verbal, social, and cyber. For each form of bullying, students were provided with several examples of what constituted such behavior. Results indicated that the general screener has good specificity but poor sensitivity, suggesting that the general screening questions were good at classifying noninvolved students but performed less well when identifying true cases of bullying. Accordingly, reports from the World Health Organization, UNICEF, and the United Nations may underestimate the prevalence of bullying among school-aged children world-wide. (Contains 3 tables.)