The purpose of this study was to develop and evaluate social skills training and parent education programs for aggressive young children and their parents in South Korea. Participants consisted of intervention group I, which included six children and their mothers in the social skills training and parent education programs; intervention group II, which included seven children and their mothers in the social skills training; and control group, which consisted of six children and their mothers. Pre-test–post-test control group design was used. Participants in both intervention groups reported a significant decrease in aggression and on improvement in pro-social behavior, emotional regulation, and social skills, while the control group reported an increase in aggressive behavior. Mothers in the intervention group I also reported an increase in warmth/acceptance. The findings indicate that both programs are highly effective in reducing aggressive behavior among young children and in fostering positive parenting behaviors.