Objective: To assess knowledge of human papillomavirus (HPV) among high school–aged adolescents. Methods: We administered written surveys to 523 inner-city high school students in Toronto, Canada, that asked about HPV, other sexually transmitted diseases (STDs), and Papanicolaou testing. We also asked them to report doctor or clinic visits and whether they received sexual health information at those visits. The predictor variables used in analysis were gender and sexual experience. Results: Eighty-seven percent of our population [95% confidence interval (CI) 84%, 89%) had not heard of HPV. Although adolescent women were more knowledgeable about Papanicolaou testing than adolescent men, only 39% of sexually experienced adolescent women knew who should get a Papanicolaou test. Sexually experienced and inexperienced adolescents failed to identify correctly their STD risk. Both genders showed greater knowledge about human immunodeficiency virus (HIV) than other diseases. Among adolescent women, 85% had visited a doctor or clinic within the past year, but only 29% had talked about sexual health. Conclusion: Knowledge of HPV infection and cervical cancer screening was low in this urban adolescent population. Improved efforts are needed for prevention of HPV infection and HPV-related cervical changes. Programs modeled after HIV-education programs might be effective. Doctors’ offices and clinics providing health care to adolescents should take greater responsibility in sexual health education.