Abstract
The purpose of present study is to determine effectiveness of cooperative learning on the social skills of first grade elementary school girl students. For this reason, 74 students of first grade elementary school (37 experimental groups and 37 control group) were selected by the random taking samples. The method of this study is quasi-experimental method by pre-test-post-test with control group. Research measures are a list of evaluation of social skills (Matson, 1983). In order to analyse the data, independent T-Test on gain scores were used. Finding showed from social skills viewpoint, the experimental group significantly higher than the control group. The results indicate that cooperative learning method in comparison with traditional method has more influence on social skills of students.