Studies on human papillomavirus (HPV) prevention education and its educational effects for elementary school students are necessary. This study aimed to examine the effects of human papillomavirus (HPV) prevention education on knowledge about cervical cancer, HPV, immunization, and attitude about immunization among girls in the sixth grade elementary school of South Korea. A quasi-experimental pretest-posttest control group design is used. The sample included 131 girls (Intervention: n = 65, Control: n = 66) in the sixth grade elementary school of South Korea. Human papillomavirus (HPV) prevention education included the contents of the definition of human papillomavirus, types of human papillomavirus, human-papillomavirus-related diseases, cervical cancer, human papillomavirus prevention methods, types of vaccines, vaccination effects, vaccination costs, vaccination frequency for 12-year-old girls, and recommended vaccination age. Human papillomavirus (HPV) prevention education was applied on the intervention group in a total of one 40-minute class in the classroom. There were statistically significant differences in knowledge about cervical cancer (t = 9.712, p < 0.001), knowledge about HPV (t = 9.638, p < 0.001), knowledge about immunization (t = 5.178, p < 0.001), and attitude about immunization (t = 3.113, p= 0.002) between the groups. This study suggests that human papillomavirus (HPV) prevention education was an effective intervention for improving knowledge about cervical cancer, knowledge about HPV, knowledge about immunization, and attitude about immunization. In public health education, human papillomavirus (HPV) prevention education can be implied for Korean girls in sixth grade elementary school.