Promoting young children’s interpersonal safety knowledge, intentions confidence and skills is the goal of many child maltreatment prevention programs; however, evaluation of their effectiveness has been limited. In this study, a randomized controlled trial was conducted examining the effectiveness of the Australian protective behaviors program, Learn to be safe with Emmy and friends™ compared to a waitlist condition. In total, 611 Australian children in Grade 1 (5–7 years; 50% male) participated, with assessments at Pre-intervention, Post-intervention and a 6-month follow-up. This study also included a novel assessment of interpersonal safety skills through the Observed Protective Behaviors Test (OPBT). Analyses showed participating in Learn to be safe with Emmy and friends™ was effective post-program in improving interpersonal safety knowledge (child and parent-rated) and parent-rated interpersonal safety skills. These benefits were retained at the 6-month follow-up, with participating children also reporting increased disclosure confidence. However, Learn to be safe with Emmy and friends™ participation did not significantly impact children’s disclosure intentions, safety identification skills, or interpersonal safety skills as measured by the OPBT. Future research may seek to evaluate the effect of further parent and teacher integration into training methods and increased use of behavioral rehearsal and modelling to more effectively target specific disclosure intentions and skills.