Child sexual abuse (CSA) threatens children's safety and even their lives. CSA is increasing steadily, despite the government's efforts to decrease and prevent its incidence. The purpose of this study was to evaluate the effects of the Child Sexual Abuse Prevention Education (C-SAPE) program on fifth-grade elementary school students' competence in terms of their knowledge and self-protective behaviors. Participants included 39 children who completed the C-SAPE program and a control group of 50 children. A nonequivalent control group pre-/posttest design was used to examine the effectiveness of C-SAPE. Significant differences were found between the experimental and control groups' mean difference (post-pre) in competence scores (t = 3.354, p = 0.001), especially in the category of self-protective behaviors (t = 2.641, p = 0.010). The C-SAPE program may be effective in increasing elementary school students' self-protective behaviors related to sexual abuse.