This study investigated the effects of group art therapy using fabric medium on the sociality of middle school students. The participants were 18 second year students (experimental group 9, control group 9)at a middle school in an urban area. The group therapy program ran a total of 12 sessions from September 4, 2012 to October 25, 2012, twice a week. The instrument for this study was Kim's(2002) sociality scale modified from the sociality section in Jeong's(1971) personality inventory test. A t-test was conducted to check the homogeneity between the experimental and control group. A two-way ANOVA with repeated measures was conducted to examine the statistical significances of the program between groups(experimental and control) and test-periods(pre, post, and follow-up test). The results are as follows: First, the study found that group art therapy using fabric medium had positive effects on the sociality of middle school students. The subcategories such as law keeping, cooperativeness, sociableness, independence showed positive effects. The subcategory independence did not show continued effects. Second, as the group art therapy program progressed, the participants were observed changing from inactive and non-cooperative attitudes to active, open, and interactive attitudes. These findings show that group art therapy using fabric medium had positive effects on the sociality of middle school students. The significance of this study is that this study showed the possibility of using fabric medium in art therapy.