The purpose of this study was to develop an intervention program for the improvement of the emotion regulation of 5-year-olds and to analyze the effects of this program on their emotion regulation and social behavior. The participants consisted of 56 5-year-olds from two day care center located in a metropolitan area of Korea. The experimental group (n=28) participated in the intervention program, and the comparative group (n=28) did not. This intervention program was developed to deal with peer relationships, and consists of activities designed to cover all domains of the Korean National Early Education Standard. The emotion regulation and social behavior were measured before and after the experiment. The data were analyzed making use of ANCOVA. Our results indicate that this program had the effect of improving the emotion regulation and social behavior on the part of 5-year-olds.