The purpose of this study is to find out the effectiveness of the leadership development group guidance program for leadership life skill and school adjustment of elementary school students. To achieve this purpose, 2 classes from the 3th grade of 5 classes of Y elementary school in Chung-nam Chon-an were selected as subjects. Then a pre-test of the leadership life skill and school adjustment was given to subjects. 34 students of researcher\'s class were placed in experimental group, while other 34 students who had same quality with the experimental group were place in control group. The experimental group were participated in 10 terms of leadership development group guidance program during 4 weeks while the control group weren\'t. The post test was administered after the experiment, and the delayed test was administered after 3 months. To verifying the effects of this program, SPSS win(11.0) was used for quantitative analysis. And opinion documents after the program for each term, research of students behavior was used for qualitative analysis. The results were as follows; First, leadership development group guidance program had a positive effect on leadership life skills of elementary school students. These were especially self-understanding skills, communication skills, decision-making skills, relationship skills. Second, leadership development group guidance program had positive effects on school adjustment. The research has been done after 3 months showed positive effects. This shows that as time goes by the experience of the leadership development program has a influence on the adjustment of school life.