Children and adolescents with intellectual disabilities are at substantially elevated risk for sexual abuse, yet developmentally appropriate and empirically evaluated prevention programs remain limited, particularly for individuals with moderate intellectual disability (MID). This study aimed to evaluate the effectiveness of a family-inclusive, visually supported, and role-playing-based sexual abuse prevention intervention grounded in Behavioral Skills Training (BST) principles. A pre-experimental pretest-posttest design was employed with 20 children with moderate intellectual disability (aged 10-17 years) and their parents recruited from a Barrier-Free Living Center. Children participated in individualized sessions focusing on body privacy, discrimination between appropriate and inappropriate touch, boundary setting, refusal skills, and help-seeking/reporting behaviors, while parents received parallel training to support and reinforce these skills at home. Outcomes were assessed using structured, performance-based child and parent knowledge-awareness forms and the Child Neglect and Abuse Awareness Scale for Parents (CNAASP). Pre-post comparisons were conducted using Wilcoxon signed-rank tests and paired samples t-tests. Results showed statistically significant improvements across all child and parent subscales and total scores following the intervention (p < .001). The largest gains among children were observed in boundary setting, refusal ("saying no"), and reporting behaviors, indicating enhanced behavioral safety skills. Parents also showed significant increases in awareness across all CNAASP domains, particularly in sexual abuse and reporting processes. These findings suggest that family-inclusive, visually supported, and practice-oriented interventions may contribute to the development of foundational safety knowledge and behavioral competencies among children with MID, while also potentially enhancing parental protective capacity.