There is limited research using small-scale simulation in applied behavior analysis. We used small-scale simulation to train firearm safety skills to 3- to 5-year-old children and assessed whether the skills generalized to the natural environment through in situ assessment. Three participants completed the training, and all participants learned the safety skills from simulation training. Two of the participants acquired the safety skills after the first simulation training, and the third participant required one booster training before demonstrating the safety skills in the natural environment.