Child sexual abuse (CSA) is a severe problem in Indonesia. Adequate knowledge in children about CSA prevention is essential so that children do not become victims. Lack of adequate children’s knowledge of the prevention of CSA may put them at risk for experiencing CSA. This cross-sectional study explores the association factors between knowledge and characteristics regarding the prevention of CSA. The study was conducted in Bandung Regency, West Java, Indonesia. Students from grades two to nine at two elementary schools were eligible for the study. Results showed that as sources of information associated with better knowledge of CSA prevention (p = 0.00), teachers and parents significantly contributed to CSA information. Multivariate analysis showed that teachers (OR: 33.479, 95% (CI: 4.467–250.912)) and parents (OR: 45.336, 95% (CI: 10.886–188.807)) significantly contributed as a source of CSA information among students. The findings are essential important implications for interventions intended at preventing CSA. Sexual education programs should be officially applied at schools for children with the support of their parents and teachers.