To investigate the effect of community of inquiry method on developing self esteem, based on Lipman's theory, an experiment was designed and conducted in Tehran primary school students o third, fourth and fifth grades. 190 student (97 boys and 93 girls) randomly selected and assigned to experimental and control group (88 experimental, 102 control). The experimental group was taught based on community of inquiry method for twelve, ninety-minutes, sessions Cooper Smith test was used as an instrument of the study for collecting data about self esteem. Results show that means of boty experimental and control group on pre-test didn't have any significant difference. But, the results of pre-test and post-test of both experimental and control group indicated that the mean of post-test scores of experimental group in relation to pre-test in self esteem has increased, while the mean of control group hasn't difference in post-test, and the mean of experimental group in post-test is higher than the mean of control group. Besides, to investigate the persistence of treatment effect, the students were rechecked after 4 months. It has shown that the results were stable. Therefore, this semi-experimental study has shown that community of inquiry method has positively affected interpersonal relationship skills in experimental group and continues for 4 month.