Child maltreatment is a global public health problem, and school-based universal prevention programs such as the Speak Up Be Safe (SUBS) curriculum can be an effective solution to help address child violence. This randomized control study employed a pre-, post-, and six-month follow-up design for students in kindergarten to grade 8, approximately ages 5-13 (n = 2797). Surveys measured the efficacy of the curriculum in increasing students' knowledge of safety rules and self-protection strategies. The analyses explored the differences at follow-up between the conditions for each index/scale for each grade using an analysis of covariance, which controlled for the pre-survey scores. The SUBS group had significantly higher scores at follow-up than the students in the control group. This study showed that the students learned new knowledge and skills to act upon and identify child abuse and neglect in keeping themselves and others safe. Policy- and decision makers now know that as a child maltreatment prevention program, SUBS can be implemented universally in schools at a low cost, delivering an essential evidence-based safety curriculum that protects students from child maltreatment.